Volume A:

Definition of the CIDOC Conceptual Reference Model

 

 

 

 

 

Produced by the CIDOC CRM

Special Interest Group

 

 

 

 

Version 7.1.3

 

February 2024

 

 

 

 

Editors: Chryssoula Bekiari, George Bruseker, Erin Canning, Martin Doerr,
Philippe Michon, Christian-Emil Ore, Stephen Stead, Athanasios Velios

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CC BY 4.0  2022 Individual Contributors to CIDOC CRM 7.1.3

 

This page is left blank on purpose


 

Table of Contents

 

Introduction............................................................................................................................................................................................. 9

Objectives of the CIDOC CRM.................................................................................................................................................... 9

Scope of the CIDOC CRM.......................................................................................................................................................... 10

Compatibility with the CIDOC CRM........................................................................................................................................ 11

Terminology.................................................................................................................................................................................... 11

Applied Form................................................................................................................................................................................. 19

Naming Conventions................................................................................................................................................... 20

Inheritance and Transitivity........................................................................................................................................ 21

Shortcuts......................................................................................................................................................................... 21

About the logical expressions used in the CIDOC CRM...................................................................................... 21

Property Quantifiers..................................................................................................................................................... 23

Modelling principles........................................................................................................................................................................... 25

Reality, Knowledge Bases and CIDOC CRM.......................................................................................................................... 25

Authorship of Knowledge Base Contents................................................................................................................................. 26

Extensions of CIDOC CRM........................................................................................................................................................ 27

Minimality...................................................................................................................................................................................... 29

Monotonicity.................................................................................................................................................................................. 29

Disjointness.................................................................................................................................................................................... 31

Introduction to the basic concepts..................................................................................................................................................... 33

Relations with Events................................................................................................................................................................... 34

Spatial Relations........................................................................................................................................................... 37

Temporal Relations...................................................................................................................................................... 39

Spatiotemporal Relations............................................................................................................................................ 40

Specific Modelling Constructs.................................................................................................................................................... 42

About Types................................................................................................................................................................... 42

Temporal Relation Primitives based on fuzzy boundaries.................................................................................... 43

Class & Property Hierarchies............................................................................................................................................................ 47

CIDOC CRM Class Hierarchy.................................................................................................................................................... 48

CIDOC CRM Property Hierarchy.............................................................................................................................................. 51

CIDOC CRM Properties of Properties (.1 Properties)........................................................................................... 54

CIDOC CRM Class Declarations...................................................................................................................................................... 56

E1 CRM Entity.............................................................................................................................................................................. 57

E2 Temporal Entity....................................................................................................................................................................... 57

E3 Condition State........................................................................................................................................................................ 58

E4 Period......................................................................................................................................................................................... 59

E5 Event.......................................................................................................................................................................................... 60

E6 Destruction................................................................................................................................................................................ 62

E7 Activity...................................................................................................................................................................................... 62

E8 Acquisition................................................................................................................................................................................ 63

E9 Move.......................................................................................................................................................................................... 65

E10 Transfer of Custody.............................................................................................................................................................. 65

E11 Modification........................................................................................................................................................................... 66

E12 Production............................................................................................................................................................................... 67

E13 Attribute Assignment............................................................................................................................................................ 68

E14 Condition Assessment.......................................................................................................................................................... 69

E15 Identifier Assignment........................................................................................................................................................... 69

E16 Measurement.......................................................................................................................................................................... 70

E17 Type Assignment................................................................................................................................................................... 71

E18 Physical Thing....................................................................................................................................................................... 71

E19 Physical Object...................................................................................................................................................................... 72

E20 Biological Object................................................................................................................................................................... 73

E21 Person...................................................................................................................................................................................... 73

E22 Human-Made Object............................................................................................................................................................ 74

E24 Physical Human-Made Thing.............................................................................................................................................. 74

E25 Human-Made Feature........................................................................................................................................................... 75

E26 Physical Feature..................................................................................................................................................................... 76

E27 Site........................................................................................................................................................................................... 76

E28 Conceptual Object................................................................................................................................................................. 77

E29 Design or Procedure............................................................................................................................................................. 78

E30 Right........................................................................................................................................................................................ 79

E31 Document................................................................................................................................................................................ 79

E32 Authority Document............................................................................................................................................................. 79

E33 Linguistic Object................................................................................................................................................................... 80

E34 Inscription............................................................................................................................................................................... 81

E35 Title.......................................................................................................................................................................................... 81

E36 Visual Item.............................................................................................................................................................................. 82

E37 Mark........................................................................................................................................................................................ 82

E39 Actor........................................................................................................................................................................................ 83

E41 Appellation............................................................................................................................................................................. 83

E42 Identifier................................................................................................................................................................................. 85

E52 Time-Span............................................................................................................................................................................... 85

E53 Place........................................................................................................................................................................................ 87

E54 Dimension............................................................................................................................................................................... 88

E55 Type......................................................................................................................................................................................... 89

E56 Language................................................................................................................................................................................. 89

E57 Material................................................................................................................................................................................... 90

E58 Measurement Unit................................................................................................................................................................. 90

E59 Primitive Value...................................................................................................................................................................... 91

E60 Number................................................................................................................................................................................... 92

E61 Time Primitive....................................................................................................................................................................... 92

E62 String....................................................................................................................................................................................... 93

E63 Beginning of Existence........................................................................................................................................................ 93

E64 End of Existence.................................................................................................................................................................... 94

E65 Creation................................................................................................................................................................................... 94

E66 Formation................................................................................................................................................................................ 95

E67 Birth......................................................................................................................................................................................... 95

E68 Dissolution.............................................................................................................................................................................. 96

E69 Death....................................................................................................................................................................................... 96

E70 Thing........................................................................................................................................................................................ 97

E71 Human-Made Thing.............................................................................................................................................................. 97

E72 Legal Object........................................................................................................................................................................... 98

E73 Information Object................................................................................................................................................................ 98

E74 Group....................................................................................................................................................................................... 99

E77 Persistent Item..................................................................................................................................................................... 100

E78 Curated Holding.................................................................................................................................................................. 101

E79 Part Addition........................................................................................................................................................................ 102

E80 Part Removal....................................................................................................................................................................... 103

E81 Transformation.................................................................................................................................................................... 103

E83 Type Creation....................................................................................................................................................................... 104

E85 Joining................................................................................................................................................................................... 105

E86 Leaving................................................................................................................................................................................. 105

E87 Curation Activity................................................................................................................................................................. 106

E89 Propositional Object........................................................................................................................................................... 106

E90 Symbolic Object.................................................................................................................................................................. 107

E92 Spacetime Volume.............................................................................................................................................................. 108

E93 Presence................................................................................................................................................................................ 109

E94 Space Primitive................................................................................................................................................................... 109

E95 Spacetime Primitive............................................................................................................................................................ 110

E96 Purchase................................................................................................................................................................................ 111

E97 Monetary Amount............................................................................................................................................................... 112

E98 Currency................................................................................................................................................................................ 112

E99 Product Type........................................................................................................................................................................ 113

CIDOC CRM Property Declarations.............................................................................................................................................. 114

P1 is identified by (identifies)................................................................................................................................................... 115

P2 has type (is type of)............................................................................................................................................................... 116

P3 has note.................................................................................................................................................................................... 116

P4 has time-span (is time-span of)........................................................................................................................................... 117

P5 consists of (forms part of).................................................................................................................................................... 118

P7 took place at (witnessed)...................................................................................................................................................... 118

P8 took place on or within (witnessed).................................................................................................................................... 119

P9 consists of (forms part of).................................................................................................................................................... 120

P10 falls within (contains)......................................................................................................................................................... 120

P11 had participant (participated in)........................................................................................................................................ 121

P12 occurred in the presence of (was present at).................................................................................................................. 122

P13 destroyed (was destroyed by)............................................................................................................................................ 122

P14 carried out by (performed)................................................................................................................................................. 123

P15 was influenced by (influenced)......................................................................................................................................... 124

P16 used specific object (was used for).................................................................................................................................. 124

P17 was motivated by (motivated)........................................................................................................................................... 125

P19 was intended use of (was made for):............................................................................................................................... 126

P20 had specific purpose (was purpose of)............................................................................................................................ 126

P21 had general purpose (was purpose of)............................................................................................................................. 127

P22 transferred title to (acquired title through)...................................................................................................................... 128

P23 transferred title from (surrendered title through)........................................................................................................... 128

P24 transferred title of (changed ownership through).......................................................................................................... 129

P25 moved (moved by).............................................................................................................................................................. 129

P26 moved to (was destination of)........................................................................................................................................... 130

P27 moved from (was origin of)............................................................................................................................................... 130

P28 custody surrendered by (surrendered custody through)............................................................................................... 131

P29 custody received by (received custody through)........................................................................................................... 131

P30 transferred custody of (custody transferred through).................................................................................................... 132

P31 has modified (was modified by)....................................................................................................................................... 132

P32 used general technique (was technique of)..................................................................................................................... 133

P33 used specific technique (was used by)............................................................................................................................. 134

P34 concerned (was assessed by)............................................................................................................................................. 134

P35 has identified (was identified by)..................................................................................................................................... 135

P37 assigned (was assigned by)................................................................................................................................................ 135

P38 deassigned (was deassigned by)....................................................................................................................................... 136

P39 measured (was measured by)............................................................................................................................................ 137

P40 observed dimension (was observed in)........................................................................................................................... 137

P41 classified (was classified by)............................................................................................................................................. 138

P42 assigned (was assigned by)................................................................................................................................................ 139

P43 has dimension (is dimension of)....................................................................................................................................... 139

P44 has condition (is condition of).......................................................................................................................................... 140

P45 consists of (is incorporated in).......................................................................................................................................... 140

P46 is composed of (forms part of).......................................................................................................................................... 141

P48 has preferred identifier (is preferred identifier of)........................................................................................................ 142

P49 has former or current keeper (is former or current keeper of)..................................................................................... 142

P50 has current keeper (is current keeper of)......................................................................................................................... 143

P51 has former or current owner (is former or current owner of)...................................................................................... 144

P52 has current owner (is current owner of).......................................................................................................................... 144

P53 has former or current location (is former or current location of)................................................................................ 145

P54 has current permanent location (is current permanent location of)............................................................................ 146

P55 has current location (currently holds).............................................................................................................................. 146

P56 bears feature (is found on)................................................................................................................................................. 147

P57 has number of parts............................................................................................................................................................. 148

P59 has section (is located on or within)................................................................................................................................ 148

P62 depicts (is depicted by)....................................................................................................................................................... 149

P65 shows visual item (is shown by)....................................................................................................................................... 150

P67 refers to (is referred to by)................................................................................................................................................. 150

P68 foresees use of (use foreseen by)...................................................................................................................................... 151

P69 has association with (is associated with)......................................................................................................................... 152

P70 documents (is documented in).......................................................................................................................................... 153

P71 lists (is listed in).................................................................................................................................................................. 153

P72 has language (is language of)............................................................................................................................................ 154

P73 has translation (is translation of)...................................................................................................................................... 154

P74 has current or former residence (is current or former residence of)........................................................................... 155

P75 possesses (is possessed by)................................................................................................................................................ 155

P76 has contact point (provides access to)............................................................................................................................. 155

P79 beginning is qualified by.................................................................................................................................................... 156

P80 end is qualified by............................................................................................................................................................... 156

P81 ongoing throughout............................................................................................................................................................. 157

P82 at some time within............................................................................................................................................................. 158

P86 falls within (contains)......................................................................................................................................................... 158

P89 falls within (contains)......................................................................................................................................................... 159

P90 has value............................................................................................................................................................................... 159

P91 has unit (is unit of).............................................................................................................................................................. 160

P92 brought into existence (was brought into existence by)............................................................................................... 160

P93 took out of existence (was taken out of existence by).................................................................................................. 161

P94 has created (was created by).............................................................................................................................................. 162

P95 has formed (was formed by).............................................................................................................................................. 162

P96 by mother (gave birth)........................................................................................................................................................ 163

P97 from father (was father for)............................................................................................................................................... 163

P98 brought into life (was born)............................................................................................................................................... 164

P99 dissolved (was dissolved by)............................................................................................................................................. 164

P100 was death of (died in)....................................................................................................................................................... 165

P101 had as general use (was use of)...................................................................................................................................... 165

P102 has title (is title of)............................................................................................................................................................ 166

P103 was intended for (was intention of)............................................................................................................................... 167

P104 is subject to (applies to)................................................................................................................................................... 167

P105 right held by (has right on).............................................................................................................................................. 168

P106 is composed of (forms part of)....................................................................................................................................... 168

P107 has current or former member (is current or former member of)............................................................................. 169

P108 has produced (was produced by).................................................................................................................................... 171

P109 has current or former curator (is current or former curator of)................................................................................. 171

P110 augmented (was augmented by)..................................................................................................................................... 172

P111 added (was added by)....................................................................................................................................................... 172

P112 diminished (was diminished by)..................................................................................................................................... 173

P113 removed (was removed by)............................................................................................................................................. 173

P121 overlaps with...................................................................................................................................................................... 174

P122 borders with....................................................................................................................................................................... 175

P123 resulted in (resulted from)............................................................................................................................................... 175

P124 transformed (was transformed by)................................................................................................................................. 176

P125 used object of type (was type of object used in).......................................................................................................... 177

P126 employed (was employed in).......................................................................................................................................... 177

P127 has broader term (has narrower term)........................................................................................................................... 178

P128 carries (is carried by)........................................................................................................................................................ 178

P129 is about (is subject of)...................................................................................................................................................... 179

P130 shows features of (features are also found on)............................................................................................................. 179

P132 spatiotemporally overlaps with....................................................................................................................................... 180

P133 is spatiotemporally separated from................................................................................................................................ 181

P134 continued (was continued by)......................................................................................................................................... 182

P135 created type (was created by).......................................................................................................................................... 183

P136 was based on (supported type creation)........................................................................................................................ 183

P137 exemplifies (is exemplified by)...................................................................................................................................... 184

P138 represents (has representation)....................................................................................................................................... 184

P139 has alternative form (is alternative form of)................................................................................................................. 185

P140 assigned attribute to (was attributed by)....................................................................................................................... 186

P141 assigned (was assigned by)............................................................................................................................................. 187

P142 used constituent (was used in)........................................................................................................................................ 187

P143 joined (was joined by)...................................................................................................................................................... 188

P144 joined with (gained member by).................................................................................................................................... 189

P145 separated (left by)............................................................................................................................................................. 190

P146 separated from (lost member by)................................................................................................................................... 190

P147 curated (was curated by).................................................................................................................................................. 191

P148 has component (is component of).................................................................................................................................. 192

P150 defines typical parts of (defines typical wholes for)................................................................................................... 192

P151 was formed from (participated in)................................................................................................................................. 193

P152 has parent (is parent of)................................................................................................................................................... 193

P156 occupies (is occupied by)................................................................................................................................................ 194

P157 is at rest relative to (provides reference space for)..................................................................................................... 195

P160 has temporal projection (is temporal projection of).................................................................................................... 196

P161 has spatial projection (is spatial projection of)............................................................................................................ 196

P164 is temporally specified by (temporally specifies)....................................................................................................... 197

P165 incorporates (is incorporated in).................................................................................................................................... 198

P166 was a presence of (had presence)................................................................................................................................... 199

P167 was within (includes)....................................................................................................................................................... 199

P168 place is defined by (defines place)................................................................................................................................. 200

P169 defines spacetime volume (spacetime volume is defined by)................................................................................... 201

P170 defines time (time is defined by).................................................................................................................................... 201

P171 at some place within......................................................................................................................................................... 202

P172 contains............................................................................................................................................................................... 202

P173 starts before or with the end of (ends after or with the start of)................................................................................ 203

P174 starts before the end of (ends after the start of)........................................................................................................... 204

P175 starts before or with the start of (starts after or with the start of)............................................................................. 205

P176 starts before the start of (starts after the start of)......................................................................................................... 206

P177 assigned property of type (is type of property assigned)........................................................................................... 207

P179 had sales price (was sales price of)................................................................................................................................ 208

P180 has currency (was currency of)....................................................................................................................................... 209

P182 ends before or with the start of (starts after or with the end of)................................................................................ 209

P183 ends before the start of (starts after the end of)........................................................................................................... 210

P184 ends before or with the end of (ends with or after the end of).................................................................................. 211

P185 ends before the end of (ends after the end of).............................................................................................................. 212

P186 produced thing of product type (is produced by)........................................................................................................ 213

P187 has production plan (is production plan for)................................................................................................................ 214

P188 requires production tool (is production tool for)......................................................................................................... 214

P189 approximates (is approximated by)................................................................................................................................ 215

P190 has symbolic content........................................................................................................................................................ 216

P191 had duration (was duration of)........................................................................................................................................ 217

P195 was a presence of (had presence)................................................................................................................................... 217

P196 defines (is defined by)...................................................................................................................................................... 218

P197 covered parts of (was partially covered by)................................................................................................................. 218

P198 holds or supports (is held or supported by).................................................................................................................. 219

Works Cited........................................................................................................................................................................................ 221

Appendix............................................................................................................................................................................................. 231

Deprecated classes and properties............................................................................................................................................ 231

Deprecated Class Migration Instructions............................................................................................................... 231

Deprecated Property Migration Instructions......................................................................................................... 232

Amendments................................................................................................................................................................................ 234

 

 

 

 

 

 

 

 


 

Table of Tables

 

Table 1: Symbolic Operators in First-Order Logic Representation............................................................................... 22

Table 2: Temporal Relation Primitives................................................................................................................................ 46

Table 3: CIDOC CRM Class Hierarchy.............................................................................................................................. 48

Table 4: CIDOC CRM Property Hierarchy........................................................................................................................ 51

Table 5: CIDOC CRM Properties of Properties (.1 Properties) Hierarchy................................................................... 54

Table 6: Deprecated Class Migration Instructions.......................................................................................................... 231

Table 7: Deprecated Property Migration Instructions.................................................................................................... 232

 

 

 

 

 

Table of Figures

Figure 1: High Level Properties and Classes of CIDOC CRM...................................................................................... 35

Figure 2: CIDOC CRM Encoding Example (Winkelmann seeing Laocoön).............................................................. 36

Figure 3: Symbolic Representation of "Winkelmann seeing Laocoön" as an Evolution in Space and Time......... 37

Figure 4: Basic CIDOC CRM Properties and Classes for Reasoning about Spatial Information............................ 38

Figure 5: Basic CIDOC CRM Properties and Classes for Reasoning about Temporal Information........................ 39

Figure 6: Basic CIDOC CRM Properties and Classes for Reasoning with Spacetime Volumes.............................. 41

Figure 7: Explanation of Interior and Boundary and an Example of Use from P174 starts before the end of (ends after the start of)..................................................................................................................................................................................................... 45

Figure 8: Temporal entity A starts before or with the end of temporal entity B. Here A is longer than B............ 203

Figure 9: Temporal entity A starts before or with the end of temporal entity B. Here A is shorter than B........... 204

Figure 10: Temporal entity A starts before the end of temporal entity B. Here A is longer than B....................... 205

Figure 11: Temporal entity A starts before the end of temporal entity B. Here A is shorter than B....................... 205

Figure 12: Temporal entity A starts before or with the start of temporal entity B. Here A is longer than B........ 206

Figure 13: Temporal entity A starts before or with the start of temporal entity B. Here A is shorter than B....... 206

Figure 14: Temporal entity A starts before the start of temporal entity B. Here A is longer than B...................... 207

Figure 15: Temporal entity A starts before the start of temporal entity B. Here A is shorter than B..................... 207

Figure 16: Temporal entity A ends before or with the start of temporal entity B. Here A is longer than B.......... 210

Figure 17: Temporal entity A ends before or with the start of temporal entity B. Here A is shorter than B......... 210

Figure 18: Temporal entity A ends before the start of temporal entity B. Here A is longer than B........................ 211

Figure 19: Temporal entity A ends before the start of temporal entity B. Here A is shorter than B....................... 211

Figure 20: Temporal entity A ends before or with the end of temporal entity B. Here A is longer than B........... 212

Figure 21: Temporal entity A ends before or with the end of temporal entity B. Here A is shorter than B.......... 212

Figure 22: Temporal entity A ends before the end of temporal entity B. Here A is longer than B......................... 213

Figure 23: Temporal entity A ends before the end of temporal entity B. Here A is shorter than B........................ 213

 

 

Introduction

This document is the formal definition of the CIDOC Conceptual Reference Model (“CIDOC CRM”), a formal ontology intended to facilitate the integration, mediation and interchange of heterogeneous cultural heritage information and similar information from other domains, as further detailed below. The CRM is the culmination of more than two decades of standards development work by the International Committee for Documentation (CIDOC) of the International Council of Museums (ICOM). Work on the CRM itself began in 1996 under the auspices of the ICOM-CIDOC Documentation Standards Working Group. Since 2000, development of the CRM has been officially delegated by ICOM-CIDOC to the CIDOC CRM Special Interest Group (SIG). The SIG, in turn, collaborates with the ISO working group ISO/TC46/SC4/WG9 to bring the CRM to the form and status of an International Standard. This set of collaborations has resulted in the production of ISO 21127:2004, ISO 21127:2014, and ISO 21127:2023, the ISO standard editions of the CIDOC CRM. This collaboration will be continued in order to support the next update of the ISO standard edition. The present document belongs to the series of evolving versions of the formal definition of the CRM, which serve the ISO working group as community draft for the standard. Eventual minor differences, in semantics and notation, of the ISO standard text from the present, community CIDOC CRM version, which the ISO working group requires and implements, will be harmonized in the subsequent versions of the present, community CIDOC CRM formal definition document.

Objectives of the CIDOC CRM

The primary role of the CIDOC CRM is to enable the exchange and integration of information from heterogeneous sources for the reconstruction and interpretation of the past at a human scale, based on all kinds of material evidence, including texts, audio-visual material and oral tradition. It starts from, but is not limited to, the needs of museum documentation and research based on museum holdings. It aims at providing the semantic definitions and clarifications needed to transform disparate, localised information sources into a coherent global resource, be it within a larger institution, in intranets or on the Internet, and to make it available for scholarly interpretation and scientific evaluation. These goals determine the constructs and level of detail of the CIDOC CRM.

More specifically, it defines, in terms of a formal ontology, the underlying semantics of database schemata and structured documents used in the documentation of cultural heritage and scientific activities. In particular, it defines the semantics related to the study of the past and current state of our world, as it is characteristic for museums, but also or other cultural heritage institutions and disciplines. It does not define any of the terminology appearing typically as data in the respective data structures; it foresees, however, the characteristic relationships for its use. It does not aim at proposing what cultural heritage institutions should document. Rather, it explains the logic of what they actually currently document, and thereby enables semantic interoperability.

The CIDOC CRM intends, moreover, to provide a model of the intellectual structure of the respective kinds of mentioned documentation in logical terms. As such, it has not been optimised for implementation specific storage and processing factors. Actual system implementations may lead to solutions where elements and links between relevant elements of our conceptualizations are no longer explicit in a database or other structured storage system. For instance, the birth event that connects elements such as father, mother, birth date, birth place may not appear in the database, in order to save storage space or response time of the system. The CIDOC CRM provides a conceptual and technical means to explain how such apparently disparate entities are semantically and logically interconnected, and how the ability of the database to answer certain intellectual questions is affected by the omission of such elements and links.

The CIDOC CRM aims to support the following specific functionalities:

·     Inform developers of information systems as a guide to good practice in conceptual modelling, in order to effectively structure and relate information assets of cultural documentation.

·     Serve as a common language for domain experts and IT developers to formulate requirements and to agree on system functionalities with respect to the correct handling of cultural contents.

·     To serve as a formal language for the identification of common information contents in different data formats; in particular, to support the implementation of automatic data transformation algorithms from local to global data structures without loss of meaning. The latter being useful for data exchange, data migration from legacy systems, data information integration and mediation of heterogeneous sources.

·     To support associative queries against integrated resources by providing a global model of the basic classes and their associations to formulate such queries.

·     It is further believed that advanced natural language algorithms and case-specific heuristics can take significant advantage of the CIDOC CRM to resolve free text information into a formal logical form, if that is regarded beneficial. The CIDOC CRM is not thought, however, to be a means to replace scholarly text, rich in meaning, by logical forms, but only a means to identify related data.

Users of the CIDOC CRM should be aware that the definition of data entry systems requires support of community-specific terminology, guidance to what should be documented and in which sequence, and application-specific consistency controls. The CIDOC CRM does not provide such notions.

By its very structure and formalism, the CIDOC CRM is extensible and users are encouraged to create extensions for the needs of more specialized communities and applications.

Scope of the CIDOC CRM

The overall scope of the CIDOC CRM can be summarised in simple terms as the curated, factual knowledge about the past at a human scale.

However, a more detailed and useful definition can be articulated by defining both the intended scope, a broad and maximally-inclusive definition of general application principles, and the practical scope, which is expressed by the overall scope of a growing reference set of specific, identifiable documentation standards and practices that the CIDOC CRM aims to semantically describe, restricted, always, in its details to the limitations of the Intended Scope.

The reasons for these distinctions between intended and practical scope are twofold. Firstly, the CIDOC CRM is developed in a “bottom-up” manner, starting from well-understood, actual, and widely used concepts of domain experts, which are disambiguated and gradually generalized as more forms of encoding are encountered. This aims to avoid the misadaptations and vagueness that can sometimes be found in introspection-driven attempts to find overarching concepts for such a wide scope, and provides stability to the generalizations found. Secondly, it is a means to identify and keep a focus on the concepts most needed by the communities working in the scope of the CIDOC CRM and to maintain a well-defined agenda for its evolution.

The intended scope of the CIDOC CRM may, therefore, be defined as all information required for the exchange and integration of heterogeneous scientific and scholarly documentation about the past at a human scale and the available documented and empirical evidence for this. This definition requires further elaboration:

·     The term “scientific and scholarly documentation” is intended to convey the requirement that the depth and quality of descriptive information that can be handled by the CIDOC CRM should be sufficient for serious academic research. This does not mean that information intended for presentation to members of the general public is excluded, but rather that the CRM is intended to provide the level of detail and precision expected and required by museum professionals and researchers in the field.

·     As “available documented and material evidence” are regarded all types of material collected and displayed by museums and related institutions, as defined by ICOM[1], and other collections, in-situ objects, sites, monuments and intangible heritage relating to fields such as social history, ethnography, archaeology, fine and applied arts, natural history, history of sciences and technology.


 

·     The concept “documentation” includes the detailed description of individual items, in situ or within collections, groups of items, and collections as a whole, as well as practices of intangible heritage. It pertains to their current state as well as to information about their past. The CIDOC CRM is specifically intended to cover contextual information: the historical, geographical and theoretical background that gives cultural heritage collections much of their cultural significance and value.

·     The exchange of relevant information with libraries and archives, and the harmonisation of the CIDOC CRM with their models, falls within the intended scope of the CIDOC CRM.

·     Information required solely for the administration and management of cultural institutions, such as information relating to personnel, accounting, and visitor statistics, falls outside the intended scope of the CIDOC CRM.

The practical scope[2] of the CIDOC CRM is expressed in terms of the set of reference standards and de facto standards for documenting factual knowledge that have been used to guide and validate the CIDOC CRM’s development and its further evolution. The CRM covers the same domain of discourse as the union of these reference standards; this means that for data correctly encoded according to these documentation formats there can be a CIDOC CRM-compatible expression that conveys the same meaning.

Compatibility with the CIDOC CRM

Users intending to take advantage of the semantic interoperability offered by the CIDOC CRM should ensure conformance with the relevant data structures. Conformance pertains either to data to be made accessible in an integrated environment or intended for transport to other environments. Any encoding of data in a formal language that preserves the relations of the classes, properties, and inheritance rules defined by this International Standard, is regarded as conformant.

Conformance with the CIDOC CRM does not require complete matching of all local documentation structures, nor that all concepts and structures present in this International Standard be implemented. This International Standard is intended to allow room both for extensions, needed to capture the full richness of cultural documentation, and for simplification, in the interests of economy. A system will be deemed partially conformant if it supports a subset of subclasses and subproperties defined by this International Standard. Designers of the system should publish details of the constructs that are supported.

The focus of the CIDOC CRM is the exchange and mediation of structured information. It does not require the interpretation of unstructured (free text) information into a structured, logical form. Unstructured information is supported, but falls outside the scope of conformance considerations.

Any documentation system will be deemed conformant with this International Standard, regardless of the internal data structures it uses; if a deterministic logical algorithm can be constructed, that transforms data contained in the system into a directly compatible form without loss of meaning.

No assumptions are made as to the nature of this algorithm. “Without loss of meaning” signifies that designers and users of the system are satisfied that the data representation corresponds to the semantic definitions provided by this International Standard.

Terminology

The following definitions of key terminology used in this document are provided both as an aid to readers unfamiliar with object-oriented modelling terminology, and to specify the precise usage of terms that are sometimes applied inconsistently across the object-oriented modelling community for the purpose of this document. Where applicable, the editors have tried to consistently use terminology that is compatible with that of the Resource Description Framework (RDF),[3] a recommendation of the World Wide Web Consortium. The editors have tried to find a language, which is comprehensible to the non-computer expert and precise enough for the computer expert so that both understand the intended meaning.

 

class

A class is a category of items that share one or more common traits serving as criteria to identify the items belonging to the class. These properties need not be explicitly formulated in logical terms, but may be described in a text (here called a scope note) that refers to a common conceptualisation of domain experts. The sum of these traits is called the intension of the class. A class may be the domain or range of none, one or more properties formally defined in a model. The formally defined properties need not be part of the intension of their domains or ranges: such properties are optional. An item that belongs to a class is called an instance of this class. A class is associated with an open set of real-life instances, known as the extension of the class. Here “open” is used in the sense that it is generally beyond our capabilities to know all instances of a class in the world and indeed that the future may bring new instances about at any time (Open World). Therefore, a class cannot be defined by enumerating its instances. A class plays a role analogous to a grammatical noun, and can be completely defined without reference to any other construct (unlike properties, which must have an unambiguously defined domain and range). In some contexts, the terms individual class, entity or node are used synonymously with class.

For example:

Person is a class. To be a Person may actually be determined by DNA characteristics, but everyone knows what a Person is. A Person may have the property of being a member of a Group, but it is not necessary to be member of a Group in order to be a Person. It is impossible to know all the "Persons" of the past. There will be more Persons in the future.

subclass

A subclass is a class that is a specialization of another class (its superclass). Specialization or the IsA relationship means that:

1         all instances of the subclass are also instances of its superclass,

2         the intension of the subclass extends the intension of its superclass, i.e., its traits are more restrictive than that of its superclass and

3         the subclass inherits the definition of all of the properties declared for its superclass without exceptions (strict inheritance), in addition to having none, one or more properties of its own.

A subclass can have more than one immediate superclass and consequently inherits the properties of all of its superclasses (multiple inheritance). The IsA relationship or specialization between two or more classes gives rise to a structure known as a class hierarchy. The IsA relationship is transitive and may not be cyclic. In some contexts (e.g., the programming language C++) the term derived class is used synonymously with subclass.

For example:

Every Person IsA Biological Object, or Person is a subclass of Biological Object.

Also, every Person IsA Actor. A Person may die. However, other kinds of Actors, such as companies, don’t die (c.f. 2).

Every Biological Object IsA Physical Object. A Physical Object can be moved. Hence, a Person can be moved also (c.f. 3).

superclass

A superclass is a class that is a generalization of one or more other classes (its subclasses), which means that it subsumes all instances of its subclasses, and that it can also have additional instances that do not belong to any of its subclasses. The intension of the superclass is less restrictive than any of its subclasses. This subsumption relationship or generalization is the inverse of the IsA relationship or specialization.

For example:

“Biological Object subsumes Person” is synonymous with “Biological Object is a superclass of Person”. It needs fewer traits to identify an item as a Biological Object than to identify it as a Person.

intension

The intension of a class or property is its intended meaning. It consists of one or more common traits shared by all instances of the class or property. These traits need not be explicitly formulated in logical terms, but may just be described in a text (here called a scope note) that refers to a conceptualisation common to domain experts. In particular, the so-called primitive concepts, which make up most of the CIDOC CRM, cannot be further reduced to other concepts by logical terms.

extension

The extension of a class is the set of all real-life instances belonging to the class that fulfil the criteria of its intension. This set is “open” in the sense that it is generally beyond our capabilities to know all instances of a class in the world and indeed that the future may bring new instances about at any time (Open World). An information system may at any point in time refer to some instances of a class, which form a subset of its extension.

scope note

A scope note is a textual description of the intension of a class or property.

Scope notes are not formal modelling constructs, but are provided to help explain the intended meaning and application of the CIDOC CRM’s classes and properties. Basically, they refer to a conceptualisation common to domain experts and disambiguate between different possible interpretations. Illustrative example instances of classes and properties are also regularly provided in the scope notes for explanatory purposes.

instance

An instance of a class is a real-world item that fulfils the criteria of the intension of the class. Note, that the number of instances declared for a class in an information system is typically less than the total in the real world. For example, you are an instance of Person, but you are not mentioned in all information systems describing Persons.

For example:

The painting known as the “The Mona Lisa” is an instance of the class E22 Human-Made Object.

An instance of a property is a factual relation between an instance of the domain and an instance of the range of the property that matches the criteria of the intension of the property.

For example:

The Mona Lisa has former or current owner. The Louvre is an instance of the property P51 has former or current owner (is former or current owner of).

property

A property serves to define a relationship of a specific kind between two classes. The property is characterized by an intension, which is conveyed by a scope note. A property plays a role analogous to a grammatical verb, in that it must be defined with reference to both its domain and range, which are analogous to the subject and object in grammar (unlike classes, which can be defined independently). It is arbitrary, which class is selected as the domain, just as the choice between active and passive voice in grammar is arbitrary. In other words, a property can be interpreted in both directions, with two distinct, but related interpretations. Properties may themselves have properties that relate to other classes (This feature is used in this model only in order to describe dynamic subtyping of properties). Properties can also be specialized in the same manner as classes, resulting in IsA relationships between subproperties and their superproperties.

In some contexts, the terms attribute, reference, link, role or slot are used synonymously with property.

For example:

“Physical Human-Made Thing depicts CRM Entity” is equivalent to “CRM Entity is depicted by Physical Human-Made Thing”.

inverse of

The inverse of a property is the reinterpretation of a property from range to domain without more general or more specific meaning, similar to the choice between active and passive voice in some languages. In contrast to some knowledge representation languages, such as RDF and OWL, this document regards that the inverse of a property is not a property in its own right that needs an explicit declaration of being inverse of another, but an interpretation implicitly existing for any property. The inverse of the inverse of a property is identical to the property itself, i.e., its primary sense of direction.

For example:

“CRM Entity is depicted by Physical Human-Made Thing” is the inverse of “Physical Human-Made Thing depicts CRM Entity”

subproperty

 

A subproperty is a property that is a specialization of another property (its superproperty). Specialization or IsA relationship means that:

1         all instances of the subproperty are also instances of its superproperty,

2         the intension of the subproperty extends the intension of the superproperty, i.e., its traits are more restrictive than that of its superproperty,

3         the domain of the subproperty is the same as the domain of its superproperty or a subclass of that domain,

4         the range of the subproperty is the same as the range of its superproperty or a subclass of that range,

5         the subproperty inherits the definition of all of the properties declared for its superproperty without exceptions (strict inheritance), in addition to having none, one or more properties of its own.

A subproperty can have more than one immediate superproperty and consequently inherits the properties of all of its superproperties (multiple inheritance). The IsA relationship or specialization between two or more properties gives rise to the structure called a property hierarchy. The IsA relationship is transitive and may not be cyclic.

Some object-oriented programming languages, such as C++, do not contain constructs that allow for the expression of the specialization of properties as sub-properties.

Alternatively, a property may be subproperty of the inverse of another property, i.e., reading the property from range to domain. In that case:

1         all instances of the subproperty are also instances of the inverse of the other property,

2         the intension of the subproperty extends the intension of the inverse of the other property, i.e., its traits are more restrictive than that of the inverse of the other property,

3         the domain of the subproperty is the same as the range of the other property or a subclass of that range,

4         the range of the subproperty is the same as the domain of the other property or a subclass of that domain,

5         the subproperty inherits the definition of all of the properties declared for the other property without exceptions (strict inheritance), in addition to having none, one or more properties of its own. The definitions of inherited properties have to be interpreted in the inverse sense of direction of the subproperty, i.e., from range to domain.

superproperty

 

A superproperty is a property that is a generalization of one or more other properties (its subproperties), which means that it subsumes all instances of its subproperties, and that it can also have additional instances that do not belong to any of its subproperties. The intension of the superproperty is less restrictive than any of its subproperties. The subsumption relationship or generalization is the inverse of the IsA relationship or specialization. A superproperty may be a generalization of the inverse of another property.

domain

The domain is the class for which a property is formally defined. This means that instances of the property are applicable to instances of its domain class. A property must have exactly one domain, although the domain class may always contain instances for which the property is not instantiated. The domain class is analogous to the grammatical subject of the phrase for which the property is analogous to the verb. It is arbitrary which class is selected as the domain and which as the range, just as the choice between active and passive voice in grammar is arbitrary. Property names in the CIDOC CRM are designed to be semantically meaningful and grammatically correct when read from domain to range. In addition, the inverse property name, normally given in parentheses, is also designed to be semantically meaningful and grammatically correct when read from range to domain.

range

The range is the class that comprises all potential values of a property. That means that instances of the property can link only to instances of its range class. A property must have exactly one range, although the range class may always contain instances that are not the value of the property. The range class is analogous to the grammatical object of a phrase for which the property is analogous to the verb. It is arbitrary which class is selected as domain and which as range, just as the choice between active and passive voice in grammar is arbitrary. Property names in the CIDOC CRM are designed to be semantically meaningful and grammatically correct when read from domain to range. In addition, the inverse property name, normally given in parentheses, is also designed to be semantically meaningful and grammatically correct when read from range to domain.

inheritance

Inheritance of properties from superclasses to subclasses means that if an item x is an instance of a class A, then:

1         all properties that must hold for the instances of any of the superclasses of A must also hold for item x, and

2         all optional properties that may hold for the instances of any of the superclasses of A may also hold for item x.

strict

inheritance

Strict inheritance means that there are no exceptions to the inheritance of properties from superclasses to subclasses. For instance, some systems may declare that elephants are grey, and regard a white elephant as an exception. Under strict inheritance it would hold that: if all elephants were grey, then a white elephant could not be an elephant. Obviously not all elephants are grey. To be grey is not part of the intension of the concept elephant but an optional property. The CIDOC CRM applies strict inheritance as a normalization principle.

multiple

inheritance

Multiple inheritance means that a class A may have more than one immediate superclass. The extension of a class with multiple immediate superclasses is a subset of the intersection of all extensions of its superclasses. The intension of a class with multiple immediate superclasses extends the intensions of all its superclasses, i.e., its traits are more restrictive than any of its superclasses. If multiple inheritance is used, the resulting “class hierarchy” is a directed graph and not a tree structure. If it is represented as an indented list, there are necessarily repetitions of the same class at different positions in the list.

For example:

Person is both an Actor and a Biological Object.

multiple Instantiation

Multiple Instantiation is the term that describes the case that an instance of class A is also regarded as an instance of one or more other classes B1...n at the same time. When multiple instantiation is used, it has the effect that the properties of all these classes become available to describe this instance. For instance, some particular cases of destruction may also be activities (e.g., Herostratos’ deed), but not all destructions are activities (e.g., destruction of Herculaneum). In comparison, multiple inheritance describes the case that all instances of a class A are implicitly instances of all superclasses of A, by virtue of the definition of the class A, whereas the combination of classes used for multiple instantiation is a characteristic of particular instances only. It is important to note that multiple instantiation is not allowed using combinations of disjoint classes.

endurant, perdurant

“The difference between enduring and perduring entities (which we shall also call endurants and perdurants) is related to their behaviour in time. Endurants are wholly present (i.e., all their proper parts are present) at any time they are present. Perdurants, on the other hand, just extend in time by accumulating different temporal parts, so that, at any time they are present, they are only partially present, in the sense that some of their proper temporal parts (e.g., their previous or future phases) may be not present. E.g., the piece of paper you are reading now is wholly present, while some temporal parts of your reading are not present any more. Philosophers say that endurants are entities that are in time, while lacking however temporal parts (so to speak, all their parts flow with them in time). Perdurants, on the other hand, are entities that happen in time, and can have temporal parts (all their parts are fixed in time).” (Gangemi et al. 2002, pp. 166-181).

shortcut

A shortcut is a formally defined single property that represents a deduction or join of a data path in the CIDOC CRM. The scope notes of all properties characterized as shortcuts describe in words the equivalent deduction. Shortcuts are introduced for the cases where common documentation practice refers only to the deduction rather than to the fully developed path. For example, museums often only record the dimension of an object without documenting the Measurement that observed it. The CIDOC CRM declares shortcuts explicitly as single properties in order to allow the user to describe cases in which he has less detailed knowledge than the full data path would need to be described. For each shortcut, the CIDOC CRM contains in its schema the properties of the full data path explaining the shortcut.

monotonic

reasoning

Monotonic reasoning is a term from knowledge representation. A reasoning form is monotonic if an addition to the set of propositions making up the knowledge base never determines a decrement in the set of conclusions that may be derived from the knowledge base via inference rules. In practical terms, if experts enter subsequently correct statements to an information system, the system should not regard any results from those statements as invalid, when a new one is entered. The CIDOC CRM is designed for monotonic reasoning and so enables conflict-free merging of huge stores of knowledge.

disjoint

Classes are disjoint if the intersection of their extensions is an empty set. In other words, they have no common instances in any possible world.

primitive

The term primitive as used in knowledge representation characterizes a concept that is declared and its meaning is agreed upon, but that is not defined by a logical deduction from other concepts. For example, mother may be described as a female human with child. Then mother is not a primitive concept. Event however is a primitive concept.

Most of the CIDOC CRM is made up of primitive concepts.

Open World

The “Open World Assumption” is a term from knowledge base systems. It characterizes knowledge base systems that assume the information stored is incomplete relative to the universe of discourse they intend to describe. This incompleteness may be due to the inability of the maintainer to provide sufficient information or due to more fundamental problems of cognition in the system’s domain. Such problems are characteristic of cultural information systems. Our records about the past are necessarily incomplete. In addition, there may be items that cannot be clearly assigned to a given class.

In particular, absence of a certain property for an item described in the system does not mean that this item does not have this property. For example, if one item is described as Biological Object and another as Physical Object, this does not imply that the latter may not be a Biological Object as well. Therefore, complements of a class with respect to a superclass cannot be concluded in general from an information system using the Open World Assumption. For example, one cannot list “all Physical Objects known to the system that are not Biological Objects in the real world”, but one may of course list “all items known to the system as Physical Objects but that are not known to the system as Biological Objects”.

complement

The complement of a class A with respect to one of its superclasses B is the set of all instances of B that are not instances of A. Formally, it is the set-theoretic difference of the extension of B minus the extension of A. Compatible extensions of the CIDOC CRM should not declare any class with the intension of them being the complement of one or more other classes. To do so will normally violate the desire to describe an Open World. For example, for all possible cases of human gender, male should not be declared as the complement of female or vice versa. What if someone is both or even of another kind?

query containment

Query containment is a problem from database theory: A query X contains another query Y, if for each possible population of a database the answer set to query X contains also the answer set to query Y. If query X and Y were classes, then X would be superclass of Y.

interoperability

Interoperability means the capability of different information systems to communicate some of their contents. In particular, it may mean that

1          two systems can exchange information, and/or

2          multiple systems can be accessed with a single method.

Generally, syntactic interoperability is distinguished from semantic interoperability. Syntactic interoperability means that the information encoding of the involved systems and the access protocols are compatible, so that information can be processed as described above without error. However, this does not mean that each system processes the data in a manner consistent with the intended meaning. For example, one system may use a table called “Actor” and another one called “Agent”. With syntactic interoperability, data from both tables may only be retrieved as distinct, even though they may have exactly the same meaning. To overcome this situation, semantic interoperability has to be added. The CIDOC CRM relies on existing syntactic interoperability and is concerned only with adding semantic interoperability.

semantic interoperability

Semantic interoperability means the capability of different information systems to communicate information consistent with the intended meaning. In more detail, the intended meaning encompasses

1         the data structure elements involved,

2         the terminology appearing as data and

3         the identifiers used in the data for factual items such as places, people, objects etc.

Obviously, communication about data structure must be resolved first. In this case consistent communication means that data can be transferred between data structure elements with the same intended meaning or that data from elements with the same intended meaning can be merged. In practice, the different levels of generalization in different systems do not allow the achievement of this ideal. Therefore, semantic interoperability is regarded as achieved if elements can be found that provide a reasonably close generalization for the transfer or merge. This problem is being studied theoretically as the query containment problem. The CIDOC CRM is only concerned with semantic interoperability on the level of data structure elements.

property quantifier

We use the term "property quantifier" for the declaration of the allowed number of instances of a certain property that can refer to a particular instance of the range class or the domain class of that property. These declarations are ontological, i.e., they refer to the nature of the real world described and not to our current knowledge. For example, each person has exactly one father, but collected knowledge may refer to none, one or many.

universal

The fundamental ontological distinction between universals and particulars can be informally understood by considering their relationship with instantiation: particulars are entities that have no instances in any possible world; universals are entities that do have instances. Classes and properties (corresponding to predicates in a logical language) are usually considered to be universals. (after Gangemi et al. 2002, pp. 166-181).

knowledge creation process

All knowledge contained in an information system must have been introduced into that system by some human agent, either directly or indirectly. Despite this fact, many, if not most, statements within such a system will lack specific attribution of authority. That being said, in the domain of cultural heritage, it is common practice that, for the processes of collection documentation and management, there are clearly and explicitly elaborated systems of responsibility outlining by whom and how knowledge can be added and or modified in the system. Ideally these systems are specified in institutional policy and protocol documents. Thus, it is reasonable to hold that all such statements that lack explicit authority attribution within the information system can, in fact, be read as the official view of the administrating institution of that system.

Such a position does not mean to imply that an information system represents at any particular moment a completed phase of knowledge that the institution promotes. Rather, it means to underline that, in a CH context, a managed set of data, at any state of elaboration, will in fact embody an adherence to some explicit code of standards which guarantees the validity of that data within the scope of said standards and all practical limitations. So long as the information is under active management it remains continuously open to revision and improvement as further research reveals further understanding surrounding the objects of concern.

A distinct exception to this rule is represented by information in the data set that carries with it an explicit statement of responsibility.

In CIDOC CRM such statements of responsibility are expressed through knowledge creation events such as E13 Attribute Assignment and its relevant subclasses. Any information in a CIDOC CRM model that is based on an explicit creation event for that piece of information, where the creator’s identity has been given, is attributed to the authority and assigned to the responsibility of the actor identified as causal in that event. For any information in the system connected to knowledge creation events that do not explicitly reference their creator, as well as any information not connected to creation events, the responsibility falls back to the institution responsible for the database/knowledge graph. That means that for information only expressed through shortcuts such as P2 has type, where no knowledge creation event has been explicitly specified, the originating creation event cannot be deduced and the responsibility for the information can never be any other body than the institution responsible for the whole information system.

In the case of an institution taking over stewardship of a database transferred into their custody, two relations of responsibility for the knowledge therein can be envisioned. If the institution accepts the dataset and undertakes to maintain and update it, then they take on responsibility for that information and become the default authority behind its statements as described above. If, on the other hand, the institution accepts the data set and stores it without change as a closed resource, then it can be considered that the default authority remains the original steward.

transitivity

Transitivity is defined in the standard way found in mathematics or logic: A property P is transitive if the domain and range is the same class and for all instances x, y, z of this class the following is the case: If x is related by P to y and y is related by P to z, then x is related by P to z. The intention of a property as described in the scope note will decide whether a property is transitive or not. For example, the property P121 overlaps with between instances of E53 Place is not transitive, while the property P89 falls within (contains) between instances of E53 Place and the property P46 is composed of (forms part of) between instances of E18 Physical Thing are both transitive. Transitivity is especially useful when CIDOC CRM is implemented in a system with deduction.

symmetry

Symmetry is defined in the standard way found in mathematics or logic: A property P is symmetric if the domain and range are the same class and for all instances x, y of this class the following is the case: If x is related by P to y, then y is related by P to x. The intention of a property as described in the scope note will decide whether a property is symmetric or not. An example of a symmetric property is E53 Place. P122 borders with: E53 Place. The names of symmetric properties have no parenthetical form, because reading in the range-to-domain direction is the same as the domain-to-range reading.

reflexivity

Reflexivity is defined in the standard way found in mathematics or logic: A property P is reflexive if the domain and range are the same class and for all instances x, of this class the following is the case: x is related by P to itself. The intention of a property as described in the scope note will decide whether a property is reflexive or not. An example of a reflexive property is E53 Place. P89 falls within (contains): E53 Place.

Applied Form

The CIDOC CRM is an ontology in the sense used in computer science. It has been expressed as an object-oriented semantic model, in the hope that this formulation will be comprehensible to both documentation experts and information scientists alike, while at the same time being readily converted to machine-readable formats such as RDF Schema or OWL. A CRM conformant documentation system can be implemented using RDF Schema or OWL, but also in Relational or Object-Oriented schema. CIDOC CRM instances can be encoded in RDF, JSON LD, XML, OWL and others.

More specifically, the CIDOC CRM is expressed in terms of the primitives of semantic data modelling. As such, it consists of:

·   classes, which represent general notions in the domain of discourse, such as the CIDOC CRM class E21 Person which represents the notion of person;

·   properties, which represent the binary relations that link the individuals in the domain of discourse, such as the CIDOC CRM property P152 has parent linking a person to one of the person’s parent.

·   properties of properties, such as the property P14.1 in the role of, of the CIDOC CRM property P14 carried out by (see also section “About Types”).
They do not appear in the property hierarchy list, but are included as part of their base property declaration and are referred to in the class declarations. They all have the implicit quantification “many to many” (see also section “Property Quantifiers”).

Although the definition of the CIDOC CRM provided here is complete, it is an intentionally compact and concise presentation of the CIDOC CRM’s 81 classes and 160 unique properties. It does not attempt to articulate the inheritance of properties by subclasses throughout the class hierarchy (this would require the declaration of several thousand properties, as opposed to 160). However, this definition does contain all of the information necessary to infer and automatically generate a full declaration of all properties, including inherited properties.

Naming Conventions

The following naming conventions have been applied hereafter:

·     Classes are identified by numbers preceded by the letter “E” (historically, classes were sometimes referred to as “Entities”), and are named using noun phrases (nominal groups) in title case (initial capitals). For example, E63 Beginning of Existence.

·     Properties are identified by numbers preceded by the letter “P,” and are named in both directions, using verbal phrases in lower case. Properties with the character of states are named in the present tense, such as “has type”, whereas properties relating to events are named in past tense, such as “carried out”. For example, P126 employed (was employed in).

·     Property names should be read in their non-parenthetical form for the domain-to-range direction, and in parenthetical form for the range-to-domain direction. Reading a property in range-to-domain direction is equivalent to the inverse of that property. Following a current notational practice in OWL knowledge representation language, we represent inverse properties in this text by adding a letter “i” following the identification number and the parenthetical form of the full property name, such as P59i is located on or within, which is the inverse of P59 has section (is located on or within).

·     Properties with a range that is a subclass of E59 Primitive Value (such as E1 CRM Entity. P3 has note: E62 String) have no parenthetical name form because reading the property name in the range-to-domain direction is not regarded as meaningful.

·     Properties that have identical domain and range are either symmetric or transitive. Instantiating a symmetric property implies that the relation holds for both the domain-to-range and the range-to-domain directions. An example of this is E53 Place. P122 borders with: E53 Place. The names of symmetric properties have no parenthetical form, because reading in the range-to-domain direction is the same as the domain-to-range reading. Transitive asymmetric properties, such as E4 Period. P9 consists of (forms part of): E4 Period, do have a parenthetical form that relates to the meaning of the inverse direction.

·     The choice of property domains, and hence the order of their names, is established in accordance with the following priority list:

-  Temporal Entity and its subclasses

-  Thing and its subclasses

-  Actor and its subclasses

-  Other

·   Properties of properties are identified by “P”, followed by the number of the base property extended with “.1” and are named in one direction using a verbal phrase in lower case in the present tense. For example: the property P62.1 mode of depiction of the property P62 depicts (is depicted by).

Inheritance and Transitivity

CIDOC CRM is formulated as a class system with inheritance. A property P with domain A and range B will also be a property between any possible subclasses of A and of B. In many cases there will be a common subclass C of both A and B. In these cases, when the property is restricted to C, that is, with C as domain and range, the restricted property could be transitive. For instance, an E73 Information Object can be incorporated into an E90 Symbolic Object and thus an information object can be incorporated in another information object.

In the definition of CIDOC CRM the transitive properties are explicitly marked as such in the scope notes. All unmarked properties should be considered as not transitive.

Shortcuts

Some properties are declared as shortcuts of longer, more comprehensively articulated paths that connect the same domain and range classes as the shortcut property through one or more intermediate classes. For example, the property E18 Physical Thing. P52 has current owner (is current owner of): E39 Actor, is a shortcut for a fully articulated path from E18 Physical Thing through E8 Acquisition to E39 Actor. An instance of the fully-articulated path always implies an instance of the shortcut property. However, the inverse may not be true; an instance of the fully-articulated path cannot always be inferred from an instance of the shortcut property inside the frame of the actual knowledge base.

The class E13 Attribute Assignment allows for the documentation of how the assignment of any property came about, and whose opinion it was, even in cases of properties not explicitly characterized as “shortcuts”.

About the logical expressions used in the CIDOC CRM

The present CIDOC CRM specifications are annotated with logical axioms, providing an additional formal expression of the CIDOC CRM ontology. This section briefly introduces the assumptions that are at the basis of the logical expression of the CIDOC CRM (for a fully detailed account of the logical expression of semantic data modelling, see (Reiter,1984)).

In terms of semantic data modelling, classes and properties are used to express ontological knowledge by means of various kinds of constraints, such as sub-class/sub-property links, e.g., E21 Person is a sub-class of E20 Biological Object, or domain/range constraints, e.g., the domain of P152 has parent is class E21 Person.

In contrast, first-order logic-based knowledge representation relies on a language for formally encoding an ontology. This language can be directly put in correspondence with semantic data modelling in a straightforward way:

·     classes are named by unary predicate symbols; conventionally, we use E21 as the unary predicate symbol corresponding to class E21 Person;

·     properties are named by binary predicate symbols; conventionally, we use P152 as the binary predicate symbol corresponding to property P152 has parent.

·     properties of properties, “.1 properties” are named by ternary predicate symbols; conventionally, we use P14.1 as the ternary predicate symbol corresponding to property P14.1 in the role of.

Ontology is expressed in logic by means of logical axioms, which correspond to the constraints of semantic modelling. In the definition of classes and properties of the CIDOC CRM, the axioms are placed under the heading ‘In first-order logic’. There are several options for writing statements in first-order logic. In this document, a standard compact notation widely used in text books and scientific papers is used. The definition is given in table 1 below.

Table 1: Symbolic Operators In First-Order Logic Representation

Symbol

Name

Reads

Truth value

Operators

 

 

 

conjunction

and

(ö  ø) is true

if and only if both ö and ø are true

disjunction

or

(ö  ø) is true

if and only if at least one of either ö or ø is true

¬

negation

not

¬ö is true if and only if ö is false

implication

implies,

if … then ...

 (ö  ø) is true

if and only if it is not the case that ö is true and ø is false

equivalence

is equivalent to,

if … and only if …

ö  ø is true

if and only if both ö and ø are true or both ö and ø are false

Quantifiers

 

 

 

existential quantifier

exists,

there exists at least one

 

Universal quantifier

forall,

for all

 

 

For instance, the above sub-class link between E21 Person and E20 Biological Object can be formulated in first-order logic as the axiom:

(x) [E21(x) E20(x)]

(reading: for all individuals x, if x is an E21 then x is an E20).

In the definitions of classes and properties in this document the universal quantifier(s) are omitted for simplicity, so the above axiom is simply written:

E21(x) E20(x)

Likewise, the above domain constraint on property P152 has parent can be formulated in first-order logic as the axiom:

P152(x,y) E21(x)

(reading: for all individuals x and y, if x is a P152 of y, then x is an E21).

Properties of properties, indicated by a '.1' after the property number are described as ternary predicate symbols. For example, the property P14.1 in the role of is described as the ternary predicate symbol corresponding to property P14 carried out by (performed):

P14(x,y) E7(x)

P14(x,y) E39(y)

P14(x,y,z) [P14(x,y) E55(z)]

These basic considerations should be used by the reader to understand the logical axioms that are used into the definition of the classes and properties. Further information about the first order formulation of CIDOC CRM can be found in (Meghini & Doerr, 2018).

Property Quantifiers

Quantifiers for properties are provided for the purpose of semantic clarification only, and should not be treated as implementation recommendations. The CIDOC CRM has been designed to accommodate alternative opinions and incomplete information; all properties should therefore be implemented as optional and repeatable for their domain and range (“many to many (0,n:0,n)”). The term “cardinality constraints” is avoided here as it typically pertains to implementations.

The following table lists all possible property quantifiers occurring in this document according to their notation, together with a textual explanation. In order to provide optimal clarity, two widely accepted notations are used redundantly in this document, a verbal and a numeric one. The verbal notation uses phrases such as “one to many”, and the numerical one, expressions such as “(0,n:0,1)”. While the terms “one”, “many”, and “necessary” are fairly intuitive, the term “dependent” denotes a situation where a range instance cannot exist without an instance of the respective property. In other words, the property is “necessary” for its range (Meghini, C. & Doerr, M., 2018).

 

many to many (0,n:0,n)

Unconstrained: an individual domain instance and range instance of this property can have zero, one, or more instances of the property. In other words, the property is optional and repeatable for its domain and range.

 

one to many

(0,n:0,1)

 

An individual domain instance of this property can have zero, one, or more instances of the property, but an individual range instance cannot be referenced by more than one instance of this property. In other words, the property is optional for its domain and range, but repeatable for its domain only. This situation is sometimes called a “fan-out”.

 

many to one

(0,1:0,n)

An individual domain instance of this property can have zero or one instance of the property, but an individual range instance can be referenced by zero, one, or more instances of the property. In other words, the property is optional for its domain and range, but repeatable for its range only. This situation is sometimes called a “fan-in”.

 

many to many, necessary (1,n:0,n)

An individual domain instance of this property can have one or more instances of this property, but an individual range instance can have zero, one, or more instances of the property. In other words, the property is necessary and repeatable for its domain, and optional and repeatable for its range.

 

one to many, necessary

(1,n:0,1)

 

An individual domain instance of this property can have one or more instances of the property, but an individual range instance cannot be referenced by more than one instance of the property. In other words, the property is necessary and repeatable for its domain, and optional but not repeatable for its range. This situation is sometimes called a “fan-out”.

 

many to one, necessary

(1,1:0,n)

An individual domain instance of this property must have exactly one instance of the property, but an individual range instance can be referenced by zero, one, or more instances of the property. In other words, the property is necessary and not repeatable for its domain, and optional and repeatable for its range. This situation is sometimes called a “fan-in”.

 

one to many, dependent

(0,n:1,1)

 

An individual domain instance of this property can have zero, one, or more instances of the property, but an individual range instance must be referenced by exactly one instance of the property. In other words, this property is optional and repeatable for its domain, but necessary and not repeatable for its range. This situation is sometimes called a “fan-out”.

 

many to many, necessary, dependent (1,n:1,n)

An individual domain instance and range instance of this property must have at least one instance of this property. In other words, this property is necessary and repeatable for its domain and range.

one to many, necessary, dependent

(1,n:1,1)

An individual domain instance of this property can have one or more instances of the property, but an individual range instance must be referenced by exactly one instance of the property. In other words, the property is necessary and repeatable for its domain, and necessary but not repeatable for its range. This situation is sometimes called a “fan-out”.

 

many to one, necessary, dependent

(1,1:1,n)

An individual domain instance of this property must have exactly one instance of the property, but an individual range instance can be referenced by one or more instances of the property. In other words, the property is necessary and not repeatable for its domain, and necessary and repeatable for its range. This situation is sometimes called a “fan-in”.

 

one to one

(1,1:1,1)

An individual domain instance and range instance of this property must have exactly one instance of the property. In other words, the property is necessary and not repeatable for its domain and for its range.

 

one to one, necessary

(1,1:0,1)

An individual domain instance of this property must have exactly one instance of this property, but an individual range instance cannot be referenced by more than one instance of this property. In other words, this property is necessary and not repeatable for its domain, and optional but not repeatable for its range.

The CIDOC CRM defines some dependencies between properties and the classes that are their domains or ranges. These can be one or both of the following:

·     the property is necessary for the domain

·     the property is necessary for the range, or, in other words, the range is dependent on the property.

The possible kinds of dependencies are defined in the table above. Note that if a dependent property is not specified for an instance of the respective domain or range, it means that the property exists, but the value on one side of the property is unknown. In the case of optional properties, the methodology proposed by the CIDOC CRM does not distinguish between a value being unknown or the property not being applicable at all. For example, one may know that an object has an owner, but the owner is unknown. In a CIDOC CRM instance this case cannot be distinguished from the fact that the object has no owner at all. Of course, such details can always be specified by a textual note.

Note that the quantification of all properties of properties, “.1” properties, is “many-to-many” and, therefore, does not appear explicitly in their definitions.


 

Modelling principles

The following modelling principles have guided and informed the development of the CIDOC CRM.

Reality, Knowledge Bases and CIDOC CRM

The CIDOC CRM is a formal ontology in the sense introduced by (Guarino, 1998).[4] The present document is intended to embrace an audience not specialized in computer science and logic; therefore, it focuses on the informal semantics and on the pragmatics of the CIDOC CRM concepts, offering a detailed discussion of the main traits of the conceptualization underlying the CIDOC CRM through basic usage patterns.[5] The CIDOC CRM aims to assist sharing, connecting and integrating information from research about the past. In order to understand the function of a formal ontology of this kind, one needs to make the following distinctions:

·     The material reality. For the purpose of the CIDOC CRM, material reality is regarded as whatever has substance that can be perceived with senses or instruments. Examples are people, a forest or a settlement environment, sea, atmosphere, distant celestial or cellular micro structures, including what we assume could be potentially or theoretically perceived if we could be there, such as the centre of the Earth or the sun, and all that is past. It is constrained to space and time. What goes on in our minds or is produced by our minds is also regarded as part of the material reality, as it becomes materially evident to other people at least by our utterances, behaviour and products.

·     The units of description or particulars, i.e. the things and relations which we refer to in order to distinguish parts of reality. Examples are Mount Ida, the Taj Mahal, the formation of China by emperor Qin Shi Huang (秦始皇) in 221BC, Tut-Ankh Amun and his embalming, Prince Shotoku of Japan sending a mission to China in 607AD, the participation of Socrates in the Battle of Potidaea or the radiocarbon dating of the Iceman Ötzi (Kutschera, 2002).

A formal ontology, such as the CIDOC CRM, constitutes a controlled language for talking about particulars. I.e., it provides classes and properties for categorizing particulars as so-called “instances” in a way that their individuation, unity and relevant properties are as unambiguous as possible. For instance, Tut-Ankh Amun as instance of E21 Person is the real pharaoh from his birth to death, and not extending to his mummy, according to the specification of the class E21 Person and its properties in the CIDOC CRM.

For clarification, the CIDOC CRM does not take a position against or in favour of the existence of spiritual substance nor of substance not accessible by either senses or instruments, nor does it suggest a materialistic philosophy. However, for practical reasons, it relies on the priority of integrating information based on material evidence available for whatever human experience. The CIDOC CRM only commits to a unique material reality independent from the observer.

When descriptions of particulars are provided, reference to them shall be made by unique names, titles or constructed identifiers, all of which are instances of E41 Appellation in the CIDOC CRM, in order the reference to be independent of the context. (In contrast, reference to particulars by pronouns or enumerations of characteristic properties, such as name and birth date, are context dependent). The appellation, and the relation between the appellation and the referred item or relationship, must not be confused with the referred item and its identity. For example, Tut-Ankh Amun the name (instance of E41 Appellation) is different from Tut-Ankh Amun the person (instance of E21 Person) and also different from the relationship between name and person (P1 is identified by). Instances of CIDOC CRM classes are the real particulars, not their names, but in descriptions, names must be used as surrogates for the real things meant. Particulars are approximate individuations, like sections, of parts of reality. In other words, the uniqueness of reality does not depend on where one draws the line between the mountain and the valley.

A CIDOC CRM-compatible knowledge base (KB) (Meghini & Doerr 2018) is an instance of E73 Information Object in the CIDOC CRM. It contains (data structures that encode) formal statements representing propositions believed to be true in a reality by an observer. These statements use appellations (e.g., https://id.loc.gov/authorities/names/n79066005[6]) of ontological particulars and of CRM concepts (e.g. P100i died in). Thereby users, in their capacity of having real-world knowledge and cognition, may be able to relate these statements to the propositions they are meant to characterize, and be able to reason and research about their validity. In other words, the formal instances in a knowledge base are the identifiers, not the real things or phenomena. A special case is digital content: a KB in a computer system may contain statements about instances of E90 Symbolic Object and the real thing may be text residing within the same KB. The instance of E90 Symbolic Object and its textual representation are separate entities and they can be connected with the property P190 has symbolic content.

Therefore, a knowledge base does not contain knowledge, but statements that represent knowledge, as long as there exist people that can resolve the identifiers used to their referents. (Appellations described in a knowledge base, and not used as primary substitutes of other items, are of course explicitly declared as instances of E41 Appellation in the knowledge base.)

Authorship of Knowledge Base Contents

This section describes a recommended good practice how to relate authority to knowledge base contents.

Statements in a KB must have been inserted by some human agent, either directly or indirectly. However, these statements often make no reference to that agent, lacking attribution of authority. An example of such statements in the CIDOC CRM is information expressed through shortcuts such as P2 has type. In the domain of cultural heritage, it is common practice that the responsibility for maintaining knowledge in the KB is elaborated in institutional policy or protocol documents. Thus, it is reasonable to hold that statements which lack explicit authority attribution can be read as the official view of the administrating institution of that system, i.e., the maintainers of the KB. This does not imply that the knowledge described in the KB is complete. So long as the information is under active management, it remains continuously open to revision and improvement as further research reveals further understandings.[7] A KB does not represent a slice of reality, but the justified beliefs of its maintainers about that reality. For simplicity, we speak about a KB as representing some reality.

Statements in a KB may also carry explicit references to agents that produced them, i.e., further statements of responsibility. In CIDOC CRM such statements of responsibility are expressed though knowledge creation events such as E13 Attribute Assignment and its relevant subclasses. Any knowledge that is about an explicit knowledge creation event, where the creator’s identity has been given, is implicitly attributed to be correctly referred to in the KB by the maintaining authority, whereas the responsibility for the content created by that event is assigned to the agent identified as causal to that event.

In the special case of an institution taking over stewardship of a database transferred into their custody, two relations of responsibility for the knowledge therein can be envisioned. If the institution accepts the dataset and undertakes to maintain and update it, then they take on responsibility for that information and become the default authority behind its statements as described above. If, on the other hand, the institution accepts the data set and stores it without change as a closed resource, then it can be considered that the default authority remains the original steward like for any other scholarly document kept by the institution.

Extensions of CIDOC CRM

Since the intended scope of the CIDOC CRM is a subset of the “real” world and is therefore potentially infinite, the model has been designed to be extensible through the linkage of compatible external type hierarchies.

Of necessity, some concepts covered by the CIDOC CRM are defined in less details than others: E39 Actor and E30 Right, for example. This is a natural consequence of staying within the model’s clearly articulated practical scope in an intrinsically unlimited domain of discourse. These ‘underdeveloped’ concepts can be considered as candidate superclasses for compatible extensions, in particular for disciplines with a respective focus. Additions to the model are known as extensions while the main model is known as CRMbase.

Compatibility of extensions with the CRM means that data structured according to an extension must also remain valid as instances of CIDOC CRM base classes. In practical terms, this implies query containment: any queries based on CIDOC CRM concepts to a KB should retrieve a result set that is correct according to the model’s semantics, regardless of whether the KR is structured according to the CIDOC CRM’s semantics alone, or according to the CIDOC CRM plus compatible extensions. For example, a query such as “list all events” should recall 100% of the instances deemed to be events by the CIDOC CRM, regardless of how they are classified by the extension.

A sufficient condition for the compatibility of an extension with the CIDOC CRM is that its classes, other than E1 CRM Entity, subsume all classes of the extension, and all properties of the extension are either subsumed by CRM properties, or are part of a path for which a CIDOC CRM property is a shortcut, and that classes and properties of the extension can be well distinguished from those in the CIDOC CRM. For instance, a class “tangible object” may be in conflict with existing classes of the CIDOC CRM. Obviously, such a condition can only be tested intellectually.

The CRM provides a number of mechanisms to ensure that coverage of the intended scope can be increased on demand without losing compatibility:

1          Existing classes can be extended, either structurally as subclasses or dynamically using the type hierarchy (see section About Types below).

2          Existing properties can be extended, either structurally as subproperties, or in some cases, dynamically, using properties of properties which allow subtyping (see section About Types below).

3          Additional information that falls outside the semantics formally defined by the CIDOC CRM can be recorded as unstructured data using E1 CRM Entity. P3 has note: E62 String.

4          Extending the CIDOC CRM by superclasses and properties that pertain to a wider scope. They are called conservative extensions, if they preserve backwards compatibility with instances described with the CIDOC CRM.

Following strategies 1, 2 and 3 will have the result that the CIDOC CRM concepts subsume and thereby cover the extensions. This means that querying an extended knowledge base only with concepts of the CIDOC CRM will nevertheless retrieve all facts described via the extensions.

In mechanism 3, the information in the notes is accessible in the respective knowledge base by retrieving the instances of E1 CRM Entity that are domain of P3 has note. Keyword search will also work for the content of the note. Rules should be applied to attach a note to the item most specific for the content. For instance, details about the role of an actor in an activity should be associated with the instance of E7 Activity, and not with the instance of E39 Actor. This approach is preferable when queries relating elements from the content of such notes across the knowledge base are not expected.

In general, only concepts to be used for selecting multiple instances from the knowledge base by formal querying need to be explicitly modelled. This criterion depends on the expected scope and use of the particular knowledge base. The CIDOC CRM prioritizes modelling the kinds of facts one would like to retrieve and relate from heterogeneous content sources, potentially from different institutions. It does not, by way of contrast, focus on the modelling of facts with a more local scope such as the administrative practices internal to an institution.

Mechanism 4, conservative extension, is more complex:         

With increasing use of the CIDOC CRM, there is also a need for extensions that model phenomena from a scope wider than the original one of the CIDOC CRM, but which are also applicable to the concepts that do fall within the CIDOC CRM’s scope. When this occurs, properties of the CIDOC CRM may be found to be applicable more generally to superclasses of the extension than to those of their current domain or range in the CIDOC CRM. This is a consequence of the key principle of the CIDOC CRM to model “bottom up”, i.e. selecting the domains and ranges for properties to be as narrow as they would apply in a well understood fashion in the current scope, thus avoiding making poorly understood generalizations at risk of requiring non-monotonic correction.

The fourth mechanism for extending the CIDOC CRM by conservation extension can be seen to be split into two cases:

1          A new class or property is added to an extension of the CIDOC CRM, which is not covered by superclasses other than E1 CRM Entity or a superproperty in the CIDOC CRM respectively. In this case, all facts described only by such concepts are not accessible by queries with CIDOC CRM concepts. Therefore, the extension should publish in a compatibility statement the additional relevant high-level classes and properties needed to retrieve all facts documented with the extended model. This case is a monotonic extension.

2          The domain or range of an existing property in the CIDOC CRM is changed to a superclass of the one or the other or both, because the property is understood to be applicable beyond its originally anticipated scope. In this case, all facts described by the extension are still accessible by querying with the concepts of the CIDOC CRM, but the extension can describe additional facts that the CIDOC CRM could not. This case is a monotonic extension and generally recommended, because it enables bottom-up evolution of the model. If this change is part of a new release of the CIDOC CRM itself, it is simply backwards compatible, and this has been done frequently in the evolution of this model.

If this second case should be documented and implemented in an extension module separate from the CIDOC CRM, it may come in conflict with the current way knowledge representation languages, such as RDF/OWL, treat it, because in formal logic changing the range or domain of a property is regarded as changing the ontological meaning completely; there is no distinction between the meaning of the property independent of domain and range and the specification of the domain and range. It is, however, similar to what in logic is called a conservative extension of a theory, and necessary for an effective modular management of ontologies.

Therefore, for the interested reader, we describe here a definition of this case in terms of first-order logic, which shows how modularity can formally be achieved:

Let us assume a property P defined with domain class A and range class C also holds for a domain class B, superclass of A, and a range class D, superclass of C, in the sense of its ontological meaning in the real world. We describe this situation by introducing an auxiliary formal property P’, defined with domain class B and range class D, and apply the following logic:

                               A(x) B(x)

                               C(x) D(x)

                               P(x,y) A(x)

                               P(x,y) C(y)

                               P’(x,y) B(x)

                               P’(x,y) D(y)

Then, P’ is a conservative extension of P if: A(x) C(y) P’(x,y) P(x,y)

In other words, a separate extension module may re-declare the respective property with another identifier, preferably using the same label, and implement the above rule.

Minimality

Although the scope of the CIDOC CRM is very broad, the model itself is constructed as economically as possible:

·     CIDOC CRM classes and properties are either primitive, or they are key concepts in the practical scope.

·     Complements of CIDOC CRM classes are not declared, because, considering the Open World principle, there are no properties for complements of a class (see Terminology and first consequence of Monotonicity).

A CIDOC CRM class is declared when:

·     It is required as the domain or range of a property not appropriate to its superclass.

·     It serves as a merging point of two CIDOC CRM class branches via multiple IsA (e.g., E25 Human-Made Feature). When the branch superclasses are used for multiple instantiation of an item, this item is in the intersection of the scopes. The class resulting from multiple IsA should be narrower in scope than the intersection of the scopes of the branch superclasses.

·     It is useful as a leaf class (i.e., at the end of a CIDOC CRM branch) to domain communities building CIDOC CRM extensions or matching key domain classes from other models to the CIDOC CRM (e.g., E34 Inscription).

Monotonicity

The CIDOC CRM’s primary role is to support the meaningful integration of information in an Open World. The adoption of the Open World principle means that the CIDOC CRM itself must remain fundamentally open and knowledge bases implemented using it should be flexible enough to receive new insights. At the model level, new classes and properties within the CIDOC CRM’s scope may be found in the course of integrating more documentation records or when new kinds of relevant facts come to the attention of its maintainers. At the level of the KBs, the need to add or revise information may arise due to numerous external factors. Research may open new questions; documentation may be directed to new or different phenomena; natural or social evolution may reveal new objects of study.

It is the aim of the maintainers of the CIDOC CRM to respect the Open World principle and to follow the principle of monotonicity. Monotonicity requires that adding new classes and properties to the model or adding new statements to a knowledge base does not invalidate already modelled structures and existing statements.

A first consequence of this commitment, at the level of the model, is that the CIDOC CRM aims to be monotonic in the sense of Domain Theory. That is to say, the existing CIDOC CRM constructs and the deductions made from them should remain valid and well-formed, even as new constructs are added by extensions to the CIDOC CRM. Any extensions should be, under this method, backwards compatible with previous models. The only exception to this rule arises when a previous construct is considered objectively incorrect by the domain experts and thus subjected to corrective revision. Adopting the principle of monotonicity has active consequences for the basic manner in which classes and properties are designed and declared in the CIDOC CRM. In particular, it forbids the declaration of complement classes, i.e. classes solely defined by excluding instances of some other classes.

For example:

FRBRoo (Bekiari et al (eds). 2015) extends the CIDOC CRM. In version 2.4 of FRBRoo, F51 Name Use Activity was declared as a subclass to the CIDOC CRM class E7 Activity. This class was added in order to describe a phenomenon specific to library practice and not considered within CRM base. F51 Name Use Activity describes the practice of an instance of E74 Group adopting and deploying a name within a context for a time-span. The creation of this extension is monotonic because no existing IsA relationship or inheritance of properties in CRM base are compromised and no future extension is ruled out. By way of contrast, if, to handle this situation, a subclass “Other Activity” had been declared, a non-monotonic change would have been introduced. This would be the case because the scope note of a complement class like “Other Activities” would forbid any future declaration of specializations of E7 Activity such as F51 Name Use Activity. In the case the need arose to declare a particular specialized subclass, a non-monotonic revision would have to be made, since there would be no principled way to decide which instances of “Other Activity” were instances of the new, specialized class and which were not. Such non-monotonic changes are extremely costly to end users, compromising backwards compatibility and long-term integration.

As a second consequence, maintaining monotonicity is also required during revising or augmenting data within a CIDOC CRM compatible system. That is, existing CIDOC CRM instances, their properties and the deductions made from them, should always remain valid and well-formed, even as new instances, regarded as consistent by the domain expert, are added to the system.

For example:

If someone describes correctly that an item is an instance of E19 Physical Object, and later it is correctly characterized as an instance of E20 Biological Object, the system should not stop treating it as an instance of E19 Physical Object. This is achieved by declaring E20 Biological Object as subclass of E19 Physical Object.

This example further demonstrates that the IsA hierarchy of classes and properties can represent characteristic stages of increasing knowledge about some item during the processes of investigation and collection of evidence. Higher level classes can be used to safely classify objects whose precise characteristics are not known in the first instance. An ambiguous biological object may, for example, be classified as only a physical object. Subsequent investigation can reveal its nature as a biological object. A knowledge base constructed with CIDOC CRM classes designed to support monotonic revision allows for seeking physical objects that were not yet recognized as biological ones. This ability to integrate information with different specificity of description in a well-defined way is particularly important for large-scale information integration. Such a system supports scholars being able to integrate all information about potentially relevant phenomena into the information system without forcing an over or under commitment to knowledge about the object. Since large scale information integration always deals with different levels of knowledge of its relevant objects, this feature enables a consistent approach to data integration.

A third consequence, applied at the level of the knowledge base, is that in order to formally preserve monotonicity, when it is required to record and store alternative opinions regarding phenomena all formally defined properties should be implemented as unconstrained (many: many) so that conflicting instances of properties are merely accumulated. Thus, integrated knowledge can serve as a research tool for accumulating relevant alternative opinions around well-defined entities, whereas conclusions about the truth are the task of open-ended scientific or scholarly hypothesis building.

For example:

King Arthur’s basic life events are highly contested. Once entered in a knowledge base, he should be defined as an instance of E21 Person and treated as having existed as such within the sense of our historical discourse. The instance of E21 Person is used as the collection point for describing possible properties and existence of this individual. Alternative opinions about properties, such as the birthplace and his living places, should be accumulated without validity decisions being made during data compilation. King Arthur may be entered as a different instance, of E28 Conceptual Object, for describing him as mythological character and accumulating possibly mythological facts.

The fourth consequence of monotonicity relates to the use of time dependent properties in a knowledge base. Certain properties declared in the CIDOC CRM, such as having a part, an owner or a location, may change many times for a single item during the course of its existence. Asserting that such a property holds for some item means that that property held for some particular, undetermined time-span within the course of its existence. Consequently, one item may be the subject of multiple statements asserting the instantiation of that property without conflict or need for revision. The collection of such statements would reflect an aggregation of these instances of this property holding over the time-span of the item’s existence. If a more specific temporal knowledge is required/available, it is recommended to explicitly describe the events leading to the assertion of that property for that item. For example, in the case of acquiring or losing an item, it would be appropriate to declare the related event class such as E9 Move. By virtue of this principle, the CRM achieves monotonicity with respect to an increase of knowledge about the states of an item at different times, regardless of their temporal order.

Time-neutral properties may be specialized in a future monotonic extension by time-specific properties, but not vice-versa. Also, many properties registered do not change over time or are relative to events in the model already. Therefore, the CIDOC CRM always gives priority to modelling properties as time-neutral, and rather representing changes by events.

However, for some of these properties many databases may describe a “current” state relative to some property, such as “current location” or “current owner”. Using such a “current” state means that the database manager is able to verify the respective reality at the latest date of validity of the database. Obviously, this information is non-monotonic, i.e., it requires deletion when the state changes. In order to preserve a reduced monotonicity, these properties have time-neutral superproperties by which respective instances can be reclassified if the validity becomes unknown or no longer holds. Therefore, the use of such properties in the CRM is only recommended if they can be maintained consistently. Otherwise, they should be reclassified by their time-neutral superproperties. This holds in particular if data is exported to another repository (see also the paragraph “Authorship of Knowledge Base Contents” above).

Disjointness

Classes are disjoint if they cannot share any common instances at any time, past, present or future. That implies that it is not possible to instantiate an item using a combination of classes that are mutually disjoint or with subclasses of them (see “multiple instantiation” in section “Terminology”). There are many examples of disjoint classes in the CIDOC CRM.

A comprehensive declaration of all possible disjoint class combinations afforded by the CIDOC CRM has not been provided here; it would be of questionable practical utility and may easily become inconsistent with the goal of providing a concise definition. However, there are two key examples of disjoint class pairs that are fundamental to an effective comprehension of the CIDOC CRM:

·     E2 Temporal Entity is disjoint from E77 Persistent Item. Instances of the class E2 Temporal Entity are perdurants, whereas instances of the class E77 Persistent Item are endurants. Even though instances of E77 Persistent Item have a limited existence in time, they are fundamentally different in nature from instances of E2 Temporal Entity, because they preserve their identity between events. Declaring endurants and perdurants as disjoint classes is consistent with the distinctions made in data structures that fall within the CIDOC CRM’s practical scope.

·     E18 Physical Thing is disjoint from E28 Conceptual Object. The distinction is between material and immaterial items, the latter being exclusively human-made. Instances of E18 Physical Thing and E28 Conceptual Object differ in many fundamental ways; for example, the production of instances of E18 Physical Thing implies the incorporation of physical material, whereas the production of instances of E28 Conceptual Object does not. Similarly, instances of E18 Physical Thing cease to exist when destroyed, whereas an instance of E28 Conceptual Object perishes only when it is forgotten and its last physical carrier is destroyed.


 

 

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Introduction to the basic concepts

The following paragraphs explain the most general logic of the CIDOC CRM. The CIDOC CRM is a formalized representation of historical discourse, a formal ontology. In this capacity, it is meant to support the (re)presentation of fact based, analytic discourse about what has happened in the past in a human understandable and machine-processable manner. It achieves this function by proposing a series of formalized properties (relations) and classes. The formalized properties support the making of semantically explicit statements relating classes of things. Their formal definition logically explicates the classes of things to which they may pertain. The CIDOC CRM properties thus enable a formal, logically explicit description of relations between individual, real world items, classified under distinct ontological classes. Encoding analytic data pertaining to the past under such a system of statements provides a standard representation for data and allows the uniform application of reasoning to large sets of data.

Grounding this high-level logic is a hierarchical system of classes and relations, that provide basic ontological distinctions by which to represent historical discourse. Familiarity with the basic ontological distinctions made in the top level of the class hierarchy provides the basic entry point to understanding how to apply the CIDOC CRM for knowledge representation.

The highest-level distinction in the CIDOC CRM is represented by the top-level concepts of E77 Persistent Item, equivalent to the philosophical notion of endurant; E2 Temporal Entity, equivalent to the philosophical notion of perdurant and, further, the concept of E92 Spacetime Volume.

As an event-centric model, supporting historical discourse, the CIDOC CRM firstly enables the description of entities that are themselves time-limited processes or evolutions within the passing of time using E2 Temporal Entity and its subclasses. Their basic function is to capture the fact of something having happened over time. In addition to allowing the description of a temporal duration, the subclasses of E2 Temporal Entity are used to document the historical relations between objects, similar to the role of action verbs in a natural language phrase. The more specific subclasses of E2 Temporal Entity enable the documentation of events pertaining to individually related/affected material, social or mental objects that have been described using subclasses of E77 Persistent Item. This precise documentation is enabled through the use of specialized properties formalizing the manner of the relation or affect. Examples of specific subclasses of E2 Temporal Entity include E12 Production, which allows the representation of events of making things by humans, and E5 Event which allows the documentation, among other things, of geological events and large-scale social events such as a war. Each of these subclasses have specific properties associated to them which allow them to function to represent the specific, real-world connection between instances of E77 Persistent Item, such as the relation of an object to its time of production through P108i was produced by (E12) or the relation of a place to a geological phenomenon through P7i witnessed (E5). The entities that E2 Temporal Entity documents, being time limited processes/occurrences, are such that their existence can be declared only on the basis of direct observation or recording of the event, or indirect observation of its material outcomes. Evidence of such entities may be preserved on material objects that are permanently changed because of them. Likewise, events may have been recorded in text or remembered through oral history. E2 Temporal Entity and its subclasses are central to the CRM and essential for almost all modelling tasks (e.g., in a museum catalogue one cannot consider an object outside its production event).

The real-world entities, which the event centric modelling of the CIDOC CRM aims to enable the accurate historical description of, are captured through E77 Persistent Item and its subclasses. E77 Persistent Item is used to describe entities that are relatively stable in form through the passage of time, maintaining a recognizable identity because their significant properties do not change. Specific subclasses of E77 Persistent Item can illustrate this point. E22 Human-Made Object is used for the description of discrete, physical objects having been produced by human action, such as an artwork or monument. An artwork or monument is persistent with regards to its physical constitution. So long as it retains its general physical form, it is said to exist and to participate in the flow of historical events. E28 Conceptual Object is also used to describe persistent items, but of a mental character. It is used to describe identifiable ideas that are named and form an object of historical discourse. Its identity conditions rely in having a carrier by which it can be recalled. The entities described by E77 Persistent Item are prone to change through human activity, biological, geological or environmental processes, but are regarded to continue to exist and be the same just as long as such changes do not alter their basic identity (essence) as defined in the scope note of the relevant class.

The notion of identity is key in the application of CIDOC CRM. The properties and relations it provides are designed to allow the accurate historical description of the evolution of real-world items through time. This being the case, classes and properties are created in order to provide a definition, which will allow the accurate application of the classes or properties to the same real-world items by diverse users. Identity, in the sense of the CIDOC CRM, therefore, means that informed people are able to agree that they refer to the same, single thing in its distinction from others, both in its extent and over its time of existence. The criteria for such a determination should come from understanding the scope note of the respective CIDOC CRM class this thing is regarded to be an instance of, because communication via information systems may not leave space for respective clarifying dialogues between users. For example, the Great Sphinx of Giza may have lost part of its nose, but there is no question that we are still referring to the same monument as that before the damage occurred, since it continues to represent significant characteristics and distinctness from an overall shaping in the past, which is of archaeological relevance. Things lacking sufficient stability or differentiation, such as atmosphere, soil, clouds, waves, are not instances of E77 Persistent Item, and not suited for information integration. Discourse about such items may be documented with concepts of the CIDOC CRM as observations in relation to things of persistent identity, such as places.

Learning to distinguish and then interrelate instances of E77 Persistent Item (endurants) and instances of E2 Temporal Entity (perdurants) using the appropriate properties is key to the proper understanding and application of CIDOC CRM in order to formally represent analytic historical data. In the large majority of cases, the distinction this provides, and the subsequent elaboration of subclasses and properties is adequate to describe the content of database records in the cultural and scientific heritage domain. In exceptional cases, where there is a need to consider complex combinations of changes of spatial extent over time, the concept of spacetime (E92 Spacetime Volume) also needs to be considered. E92 Spacetime Volume describes the entities whose substance has or is an identifiable, confined geometrical extent in the material world that may vary over time, fuzzy boundaries notwithstanding. For example, the built settlement structure of the city of Athens is confined both from the point of view of time-span (from its founding until now) and from its changing geographical extent over the centuries, which may become more or less evident from current observation, historical documents and excavations. Even though E92 Spacetime Volume is an important theoretical part of the model, it can be ignored for most practical documentation and modelling tasks.

The key to the proper understanding of CIDOC CRM comes through the appropriation of its basic divisions and the logic these represent. It is important to underline that the CIDOC CRM is not intended to function as a classification system or vocabulary tool. The basic class divisions in CIDOC CRM are declared in order to be able to apply distinct properties to these classes and, in so doing, formulate precise, analytic propositions that represent historical realities. The expressive power of CIDOC CRM comes not from the application of classes to classify entities but in the documenting the interrelation of individual historical items through well-defined properties. These properties characteristically cover subjects such as relations of identifying items by names and identifiers; participation of persistent items in temporal entities; locations of temporal entities and physical things in space and time; relations of observation and assessment; part-decomposition and structural properties of anything; influence of things and experiences on the activities of people and their products; and reference of information objects to anything.

We explain these concepts with the help of graphical representations in the next sections.

Relations with Events

Figure 1 illustrates the minimal properties in the CIDOC CRM for documenting “what has happened”, the central pattern of the model. First, consider the class E1 CRM Entity, the formal top class of the model. It primarily serves a technical purpose to aggregate the ontologically meaningful concepts of the model. It declares however two important properties of general validity and distinct features of the model: P1 is identified by, with range E41 Appellation, makes the fundamental ontological distinction between the identity of a particular and an identifier (see section “Reality, Knowledge Bases and CIDOC CRM” above), and in practice allows for describing a discourse about resolving historical ambiguities of names and reconciliation of multiple identifiers. The property P2 has type, with range E55 Type, constitutes a practical interface for refining classes by terminologies, being often volatile, as detailed in the section “About Types” below.

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Figure 1: High Level Properties and Classes of CIDOC CRM

All classes in Figure 1 are direct or indirect subclasses of E1 CRM Entity, but for better readability, only the “subclass of” -link from E2 Temporal Entity is shown. The latter comprises phenomena that continuously occur over some time-span (E52 Time-Span) in the natural time dimension, but some of them may not be confined to specific area, such as a marriage status. Further specializing, E4 Period comprises phenomena occurring in addition within a specific area in the physical space, which can be specified by P7 took place at, with range E53 Place. Instances of E4 Period can be of any size, such as the Warring States Period, the Roman Period, a siege or just the process of making a signature. Further specializing, E5 Event comprises phenomena involving and affecting certain instances of E77 Persistent Item in a way characteristic of the kind of process, which can be specified by the property P12 occurred in the presence of. This concept of presence is very powerful: it constrains the existence of the involved things to the respective places within the specified time and implies the potential of passive or active involvement and mutual impact. Via presence, events represent nodes in a network of things meeting in various combinations in the course of time at different places.

The most important specializations of E77 Persistent Item in this context are: E39 Actor, those capable of intentional actions, E18 Physical Thing, having an identity bound to a relative stability of material form, and E28 Conceptual Object, the idealized things that can be recognized but have an identity independent from the materialization on a specific carrier. The property P12 occurred in the presence of has 36 direct and indirect subproperties, relating these and many more subclasses of E5 Event and E77 Persistent Item. Regardless whether a CRM-compatible knowledge base is created with these properties only or with their much more expressive specializations, querying for the five high-level properties in figure 1 will provide answer to all “Who-When-Where-What-How” questions, and allow for retrieving potentially richly elaborated stories of people, places, times and things.

This pattern of “meeting” is complemented by two more subclasses of E5 Event: E63 Beginning of Existence and E64 End of Existence, which imply not only presence, but constitute the endpoints of existence of things and people in space and time, often in explicit presence and interaction with others, be they causal by producing or consuming or just witnessing. Note that the model supports multiple instantiation. As a consequence, particular events can be instances of combinations of these and other classes, describing tightly integrated processes of multiple nature. The representation of things connected in events by presence, beginning and end of existence is sufficient to describe the logic of termini postquos and antequos, a major form of reasoning about chronology in historical studies.

As a simple, real example of applying the above concepts we present a historical event, relevant for the history of art: Johann-Joachim Winckelmann (a German Scholar) has seen the so-called Laocoön Group in 1755 in the Vatican in Rome (at display in the Cortile del Belvedere). He described his impressions in 1764 in his “History of the Art of Antiquity”, (being the first to articulate the difference between Greek, Greco-Roman and Roman art, characterizing Greek art with the famous words “…noble simplicity, silent grandeur”). The sculpture, in Hellenistic "Pergamene baroque" style (Bieber 1961, Brilliant 2000) is widely assumed to be a copy, made between 27 BC and 68 AD (following a Roman commission) from a Greek (no more extent) original. Johann-Joachim Winckelmann was born 1717 as child of Martin Winckelmann and Anna-Maria Meyer and died in 1768 in Trieste.

Figure 2 presents a semantic graph of this event, as described above, using CIDOC CRM concepts. The facts in parentheses above are omitted for better clarity. Instances of classes are represented by informative labels instead of identifiers, in boxes showing the class label above the instance label. Properties are represented as arrows with the property label attached. After class labels and property labels, the identifiers of the respective superclasses and superproperties from Figure 1 are shown in parenthesis, in order to demonstrate that the story can be represented and queried with these concepts only. It also shows how concept specialization increases expressiveness without losing genericity. It is noteworthy that the transfer of information from the Greek original, to the copy, to the mind of Winckelmann and into his writings can be solely understood by this chain of things being present in different meetings. Note also that the degree to which a fact is believed to be real does not affect the choice of CIDOC CRM concepts for description of the fact, nor the reality concept underlying the model.

A diagram of a flowchart



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Figure 2: CIDOC CRM Encoding Example (Winckelmann seeing Laocoön)

Figure 2 represents in addition one more top-level property of the CIDOC CRM: P67 refers to, which describe an evidence-based fact that an information object makes reference to an identifiable item.

As mentioned above, the central concept of the CIDOC CRM is the representation of a part of reality that can be approximated as a network of things meeting in various combinations in spacetime. Using the same example from above, Figure 3 illustrates this concept via an alternative symbolic representation. It aims at rendering the idea that people and things in the past have performed mostly unknown trajectories in spacetime, and the historical facts known to us constrain their possible whereabouts for some limited time-spans to having been together at some known or unknown place.

We use a one-dimensional representation of space, as used in archaeology to describe the spatial evolution of periods or cultures over time, and a vertical time axis. We symbolize the trajectories of things and people as fuzzy lines between events in order to render their relative indeterminacy between known events. Non-animate things use to be stationary if not transferred, whereas people may move around on their own. We symbolize events as fuzzy ovals to render the fuzzy boundaries of events in space and time. Note that in this representation, as a general pattern, things may “survive” events, emerge from events or end in events. Beginning and ending of existence impose an additional temporal order on events of causal nature, which can be stronger than explicit dates. We symbolize the unreported ends of existence of people and things, which are also events, by a dot at the end of the trajectory.

A diagram of a person and person

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Figure 3: Symbolic Representation of "Winkelmann seeing Laocoön" as an Evolution in Space and Time

In the following, we give an overview of the system of spatial and temporal relations in the CIDOC CRM, because it constitutes an important tool for precise documentation of the past and has a certain complexity that needs to be understood in a synopsis.

Spatial Relations

A major area of documentation and historical research centres around positioning in space of what has happened and the things involved, as well as reasoning about respective spatial relations. The key class CIDOC CRM provides for modelling this information is E53 Place. E53 Place is used to document geometric extents in the physical space containing actual or possible positions of things or happenings. The higher-level properties and classes of CIDOC CRM that centre around E53 Place allow for the documentation of: relations between places; recording the geometric expressions defining or approximating a place and their semantic function; tracing the history of locations of a physical object; identifying the places where an individual or group have been located; identifying places on a physical object and the spatial extent of certain temporal entities.

Geometric Expressions of Place: Contemporary documentation of spatial information has access to advanced equipment for accurately recording location and libraries of georeferenced place information. For this reason, documentation of place now often includes the recording of precise coordinates for a referenced place. Of great importance semantically, is to understand the manner in which such a geometric place expression actually relates to a referenced place. The cluster or relations P168 place is defined by, P171 at some place within, and P172 contains allows the user to link to geometric place expressions while also accurately indicating how this expression relates to the documented place. Geometric place expressions are instances of E94 Space Primitive, a primitive class for expressing values in data systems not further analysed in the CIDOC CRM. These properties provide a valid interface to the OGC standards, as elaborated in CRMgeo (Doerr & Hiebel 2013).

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Figure 4: Basic CIDOC CRM Properties and Classes for Reasoning about Spatial Information

Relations between Places: The cluster of relations P89 falls within (contains), P122 borders with, P121 overlaps with and P189 approximates can express relative relationships held between places. These properties hold between instances of E53 Place and allow interordering places using common mereotopological concepts.

History of Object Locations: Instances of place are often referenced in order to record the location of some object. When the movement of the object to different locations through time is of interest, it is also important to be able to analytically record the different locations at which an object was and at what point. The CIDOC CRM offers two top level mechanisms for tracing the relation of objects to places. If the aspect of time is unknown or not of interest, then an object can be related to a place through the properties P53 has former or current location and P55 has current location. The former property is the conservatively appropriate choice for documenting the object-to-place relation when time elements are not known. If one is actively tracking current location, the latter property is also of use. When an accurate history of the temporal aspect of location should be provided, the user should take advantage of the class E9 Move, a temporal entity class. Instantiating E9 Move allows the user to document the origin, destination and concerned object of a move event using the collection of properties P27 moved from, P26 moved to, P25 moved. Being a temporal class E9 Move further allows the tracing of time, agency etc. Note that things may be moved indirectly as parts of or within other things.

Actor Locations: Tracking the history of the location of actors is related to the history of object location with a significant difference: in the CIDOC CRM an actor is defined as an entity featuring agency which is not the case in objects and physical entities in general. Not being physical, an actor cannot be the subject of an instance of E9 Move which documents physical relocations. The CIDOC CRM thus offers the notion of P74 has current or former residence in order to document the relation of a person or group to a location as residing there at some time.

Places on a Physical Object: In the recording of cultural heritage and other scientific data, particularly about mobile objects, including ships, it is often necessary to identify where on an object or a certain feature is located and where a certain phenomenon is observed. For this, the CIDOC CRM offers the relation P59 has section relating the object to the places which are defined upon it. Note that Earth is the physical object we relate places to per default. In geological times, a narrower relation to a tectonic plate may be necessary.

Spatial Extent of Temporal Entities: In order to spatially define the extent of temporal phenomena, the CIDOC CRM offers two properties that apply to all instances of temporal entity under the class E4 Period: P7 took place at and P8 took place on or within. The former is used to relate a temporal phenomenon directly to an instance of E53 Place which provides the geometric context in which that phenomenon took place. The latter property allows the documentation of a temporal phenomenon taking place in relation to a physical object. This is useful for recording information such as the occurrence of an event on a moving ship or within a particular storage container, where the geometric location is not known or indirectly relevant.

Temporal Relations

Historical and scientific discourse about the past deals with different levels of knowledge regarding events and their temporal ordering that feed into chronology. Chronology is fundamental to understanding social and natural history, and reasoning about temporal relations and causality is directly related. An immense wealth of physical observations allows for inferring temporal relations and vice-versa. It is important to be able to document temporality both with regards to known dates but also according to relative positioning within a historical timeline. The top-level properties of the CIDOC CRM relating to temporal entities support the documentation of: dates as time-spans or dimensions, mereological relations between temporal entities as well as a complete suite of topological relations.

Dates and Durations: When some absolute dates limiting a temporal entity are known, this can be documented by instantiating the P4 has time-span property and creating an instance of E52 Time-span. Dates should then be recorded as instances of E61 Time Primitive and related to the time-span through properties P81 ongoing throughout or P82 at some time within. Time is recorded as a span and not an instant in the CIDOC CRM. The choice of property P81 ongoing throughout allows the documentation of knowledge that a temporal phenomenon was occurring at least at all points of a known time-span. The property P82 at some time within allows the weaker claim that the phenomenon must have occurred within the limits of a particular time-span without further specifying as to when precisely. It is the default for historical dates, given, for instance, in years for events of much smaller duration. The actual mode of encoding the documented date is outside the scope of the CIDOC CRM, which defines this with a primitive class, E61 Time Primitive. Finally, the property P191 had duration can be deployed in order to document a temporal phenomenon with known duration but with less precisely temporal positioning. For instance, a birth may be known with the precision of a year, but with a duration of 3 hours. For documenting exact time-spans that are result of a declaration rather than observation, for instance in order to describe a time-span multiple events may fall into, the property P170 defines time allows for specifying the time-span uniquely by a temporal primitive, rather than by P81 ongoing throughout or P82 at some time within using an identical time primitive.

Figure 5: Basic CIDOC CRM Properties and Classes for Reasoning about Temporal Information

Mereological relations: The documentation of the part-whole relationship of temporal phenomena is crucial for historical reasoning. The CIDOC CRM distinguishes under temporal entities two immediate specializations: E4 Period is a high-level concept for the documentation of temporal phenomena of change and interactions in space and time, comprising but not limited to historical periods such as Ming or Roman, and is further specialized in rich hierarchy of more specific processes and activities. The second specialization is E3 Condition State, a rather specific class for the documentation of static phases of physical things. The CIDOC CRM so far does not describe a higher-level class of static phases, because they are normally deductions from multiple observations, problematic in information integration and vulnerable to non-monotonic revision. For both classes, two different mereological relations are articulated: The property P9 consists of is used to document proper parthood between instances of E4 Period, i.e. to describe how the phenomena that make up an instance of E4 Period can causally be subdivided into more delimited phenomena. In contrast, the property P10 falls within, explained further in the section about spatiotemporal relations, describes only a non-causal co-occurrence in the same spatiotemporal extent. The property P5 consists of indicates, in analogy, proper parthood between instances of E3 Condition State.

Topological Relations: A lot of semantic relations have implications on the temporal ordering of temporal entities. For instance, meeting someone must occur after birth and before death of the involved parties. Information can only be transferred after it has been learned. On the other side, direct information about temporal order has implications on possible or impossible semantic relations. This form of reasoning is of paramount importance for research about the past. It turned out that the popular temporal relations defined by (Allen, 1983), which the CIDOC CRM had adopted in previous versions, are not well suited to describe inferences from semantic relations, as detailed in the section “Temporal Relation Primitives based on fuzzy boundaries” below. Instead, the CIDOC CRM introduces a theory of fuzzy boundaries in time that enables the accurate interpositioning of temporal entities between themselves taking into account the inherent fuzziness of temporal boundaries. This model subsumes the earlier introduced Allen temporal relations which may continue to be used in extensions of the CIDOC CRM.

Spatiotemporal Relations

Treating space and time as separate entities is normally adequate for describing events and where things are. When more precise documentation and reasoning is required about phenomena spreading out over time, such as Bronze Age, a settlement, a nation, moving reference frames such as ships, things being stored in containers and moved around, built structures being partially destroyed, rebuilt and altered etc., space and time must be understood as a coherent continuum, the so-called spacetime. This is not a familiar concept for many users, and those not interested in such details may therefore skip this section.

However, the respective model the CIDOC CRM adopts constitutes a valid interface to the OGC standards, as elaborated in CRMgeo (Doerr & Hiebel 2013) and important for connecting to GIS applications. The key class CIDOC CRM provides for modelling this information is E92 Spacetime Volume. E92 Spacetime Volume is used to document geometric extents in the physical spacetime containing actual or possible positions of things or happenings, in particular in those cases when the changes of place to be documented cannot be reduced to distinct events, because the spatial extent changes continuously. The higher-level properties and classes of CIDOC CRM that centre around E92 Spacetime Volume allow for the documentation of: relations between spacetime volumes, relations to space and time as separate entities, and treating the exact extent of physical things and periods in space at any time of their existence as spacetime volumes. Its use is particularly elegant for the description of temporal gazetteers.

Defining a Spacetime Volume: There are three ways to define a spacetime volume:

1          The property P169 defines spacetime volume should be used to declare a spatiotemporal container for some things or happenings in terms of spatial coordinates that may vary over time, be it in discrete steps or continuously with the help of spacetime expressions. The latter are instances of E95 Spacetime Primitive, a primitive class for expressing values in data systems not further analysed in the CIDOC CRM.

2          Instances of E4 Period are regarded to be specialized instances of E92 Spacetime Volume that are formed by the spreading out of the phenomena that make up an instance of E4 Period. As such they are fuzzy but in general observable.

3          The continuous sequence of spatial extent that the matter of an instance of E18 Physical Thing occupies in the course of time, defines a spacetime volume unique to it from the beginning of its existence to its end, which can also be understood as its trajectory through the universe The property P169 defines allows for referring to this spacetime volume, in order to document its additional properties. As such this spacetime volume is fuzzy but in general observable. It is not easy to make a mental picture of the spacetime volume of a physical thing, but the construct simplifies all reasoning about where things have been.

Figure 6: Basic CIDOC CRM Properties and Classes for Reasoning with Spacetime Volumes

Relations with Places and Physical Things: The property P161 has spatial projection associates a spacetime volume with the complete spatial extent it has occupied during its time-span of definition. Due to relativity of space, the definition of an instance of E53 Place must be relative to some physical thing as geometric reference. This can explicitly be documented with the property P157 is at rest relative to. If the place where something is at a certain point in time is given in multiple reference spaces in relative movement, such as with respect to a ship versus to the seafloor, these differently defined places may later move apart. Therefore, a spacetime volume, even though uniquely defined, can have any number of spatial projections, depending on the reference space. Currently, the GPS system defines a default reference space on the surface of Earth. In art conservation and other descriptions of mobile object of fixed shape, it is useful to refer to the precise place a physical thing occupies with respect to itself as reference space via P156 occupies, for further analysis. P156 occupies constitutes a particular projection of the spacetime volume of this thing. In contrast, the property P53 has former or current location only describes that a thing was within a specific place given in some reference space for an undefined time.

Relations with Time-Spans and Periods: The property P160 has temporal projection associates a spacetime volume with the complete temporal extent it has covered comprising all places of its definition. In contrast to places, the reference system of time is unique[8] except for the choice of origin. For instances of E4 Period and its subclasses, which inherit P160 has temporal projection, the property is actually identical with the property P4 has time-span inherited from E2 Temporal Entity, because is describes the temporal extent of the phenomena that make up an instance of E4 Period. Therefore, it is recommended to use P4 has time-span for instances of E4 Period and its subclasses, rather than P160 has temporal projection.

Relations of Presence: Instances of E93 Presence are specialized instances of E92 Spacetime Volume that are identical with the spatial evolution of a larger spacetime volume specified by P166 was presence of, but delimited to a, normally short, time-span declared by P164 is temporally specified by. In other words, they constitute “snapshots” or “time-slices” of another spacetime volume, such as the extent of the Roman Empire during 30AD. They are the basic construct to describe exactly where something was or happened at a particular time(-span), in connection with the property P161 has spatial projection. In particular, it allows for describing the whereabouts of mobile objects, be it in the storage of a museum, a palace, deposited in the ground, or transported in a container, such as the bone of a saint. For ease of use, a shortcut P195 was presence of is defined directly to E18 Physical Thing, bypassing the definition of its spacetime volume.

Topological Relations: Finally, the model defines truly spatiotemporal topological relations. P10 falls within (contains) is the complete inclusion of one spacetime volume in another. It should not be confused with inclusion in the spatial and temporal projection, which may be larger. For example, in 14 AD, Mesopotamia was not within the Roman Empire. Further, the properties P132 spatiotemporally overlaps with and its negation P133 is spatiotemporally separated from are fundamental to argue about temporary parthood, possible continuity etc.

Specific Modelling Constructs

About Types

Virtually all structured descriptions of museum objects begin with a unique object identifier and information about the “type” of the object, often in a set of fields with names like “classification”, “category”, “object type”, “object name”, etc. All these fields are used for terms that declare that the object belongs to a particular category of items. In the CIDOC CRM the class E55 Type comprises concepts denoted by terms. Instances of E55 Type represent concepts (universals) in contrast to instances of E41 Appellation, which are used to name instances of CIDOC CRM classes.

For this purpose, the CIDOC CRM provides two basic properties that describe classification with terminology, corresponding to what is the current practice in the majority of information systems. The class E1 CRM Entity is the domain of the property P2 has type (is type of), which has the range E55 Type. Consequently, every class in the CIDOC CRM, with the exception of E59 Primitive Value, inherits the property P2 has type (is type of). This provides a general alternative mechanism to specialize the classification of CIDOC CRM instances to any level of detail, by linking to external vocabulary sources, thesauri, classification schemas or ontologies.

Analogous to the function of the P2 has type (is type of) property, some properties in the CIDOC CRM are associated with an additional property. These are numbered in the CIDOC CRM documentation with a ‘.1’ extension. The range of these properties of properties always falls under E55 Type. The purpose of a property of a property is to provide an alternative mechanism to specialize its domain property through the use of property subtypes declared as instances of E55 Type. They do not appear in the property hierarchy list but are included as part of the property declarations and referred to in the class declarations. For example, P62.1 mode of depiction: E55 Type is associated with E24 Physical Human-Made Thing. P62 depicts (is depicted by): E1 CRM Entity.

The class E55 Type also serves as the range of properties that relate to categorical knowledge commonly found in cultural documentation. For example, the property P125 used object of type (was type of object used in) enables the CIDOC CRM to express statements such as “this casting was produced using a mould”, meaning that there has been an unknown or unmentioned object, a mould, that was actually used. This enables the specific instance of the casting to be associated with the entire type of manufacturing devices known as moulds. Further, the objects of type “mould” would be related via P2 has type (is type of) to this term. This indirect relationship may actually help in detecting the unknown object in an integrated environment. On the other side, some casting may refer directly to a known mould via P16 used specific object (was used for). So, a statistical question to how many objects in a certain collection are made with moulds could be answered correctly following both paths through P16 used specific object (was used for) - P2 has type (is type of) and P125 used object of type (was type of object used in). This consistent treatment of categorical knowledge enhances the CIDOC CRM’s ability to integrate cultural knowledge.

Types, that is, instances of E55 Type and its subclasses, can be used to characterize the instances of a CIDOC CRM class and hence refine the meaning of the class. A type ‘artist’ can be used to characterize persons through P2 has type (is type of). On the other hand, in an art history application of the CIDOC CRM it can be adequate to extend the CIDOC CRM class E21 Person with a subclass E21.xx Artist. What is the difference of the type ‘artist’ and the class Artist? From an everyday conceptual point of view there is no difference. Both denote the concept ‘artist’ and identify the same set of persons. Thus, in this setting a type could be seen as a class and the class of types may be seen as a metaclass. Since current systems do not provide an adequate control of user defined metaclasses, the CIDOC CRM prefers to model instances of E55 Type as if they were particulars, with the relationships described in the previous paragraphs.

Users may decide to implement a concept either as a subclass extending the CIDOC CRM class system or as an instance of E55 Type. A new subclass should only be created in case the concept is sufficiently stable and associated with additional explicitly modelled properties specific to it. Otherwise, an instance of E55 Type provides more flexibility of use. Users that may want to describe a discourse not only using a concept extending the CIDOC CRM but also describing the history of this concept itself, may choose to model the same concept both as subclass and as an instance of E55 Type with the same name. Similarly, it should be regarded as good practice to foresee for each term hierarchy refining a CIDOC CRM class a term equivalent of this class as top term. For instance, a term hierarchy for instances of E21 Person may begin with “Person”.

One role of E55 Type is to be the CIDOC CRM’s interface to domain specific ontologies and thesauri or less formal terminological systems. Such sets of concepts can be represented in the CIDOC CRM as subclasses of E55 Type, forming hierarchies of terms, i.e., instances of E55 Type linked via P127 has broader term (has narrower term). Such hierarchies may be extended with additional properties. Other standard models, in particular richer ones, used to describe terminological systems can also be interfaced with the CIDOC CRM by declaring their respective concept class as being equivalent to E55 Type, and their respective broader/narrower relation as being identical with P127 has broader term (has narrower term), as long as they are semantically compatible.

In addition to being an interface to external thesauri and classification systems, E55 Type is an ordinary class in the CIDOC CRM and a subclass of E28 Conceptual Object. E55 Type and its subclasses inherit all properties from this superclass. Thus, together with the CIDOC CRM class E83 Type Creation the rigorous scholarly or scientific process that ensures a type is exhaustively described and appropriately named can be modelled inside the CIDOC CRM. In some cases, particularly in archaeology and the life sciences, E83 Type Creation requires the identification of an exemplary specimen and the publication of the type definition in an appropriate scholarly forum. This is very central to research in the life sciences, where a type would be referred to as a “taxon,” the type description as a “protologue,” and the exemplary specimens as “original element” or “holotype”.

Finally, instances of E55 Type or suitable subclasses can describe universals from type systems not organized in thesauri or ontologies, such as industrial product names and types, defined and published by the producers themselves for each new product or product variant.

Temporal Relation Primitives based on fuzzy boundaries

It is characteristic for sciences dealing with the past, such as history, archaeology or geology, to derive temporal topological relations from stratigraphic and other observations and from considerations of causality between events. For this reason, the CIDOC CRM introduced, in version 3.3, the whole set of temporal relationships of Allen’s temporal logic (the now deprecated properties P114 to P120). It was regarded at that time as a well-justified, exhaustive and sufficient theory to deal with temporal topological relationships of spatiotemporal phenomena relevant to cultural historical discourse. Allen’s temporal logic is based on the assumption of known, exact endpoints of time intervals (time-spans), described by an exhaustive set of mutually exclusive relationships.

Since many temporal relations can be inferred from facts causal to them, e.g. a birth necessarily occurring before any intentional interaction of a person with other individuals, or from observations of material evidence without knowing the absolute time, the temporal relationships pertain in the CIDOC CRM to E2 Temporal Entities, and not their Time-Spans, which require knowledge of absolute time. If absolute times are known, deduction of Allen’s relation is a simple question of automated calculus and not the kind of primary scientific insight the CIDOC CRM, as a core model, is interested in. However, their application turned out to be problematic in practice for two reasons:

Firstly, facts causal to temporal relationships result in expressions that often require a disjunction (logical OR condition) of Allen’s relationships. For instance, a child may be stillborn. Ignoring states at pregnancy as it is usual in older historical sources, birth may be equal to death, meet with death or be before death. The knowledge representation formalism chosen for the CIDOC CRM however does not allow for specifying disjunctions, except within queries. Consequently, simple properties of the CIDOC CRM that imply a temporal order, such as P134 continued, cannot be declared as subproperties of the temporal relationship they do imply, which would be, in this case: “before, meets, overlaps, starts, started-by, contains, finishes, finished-by, equals, during or overlapped by” (see P174 starts before the end of).

Secondly, nature does not allow us to observe equality of points in time. There are three possible interpretations to this fact. Common to all three interpretations is that they can be described in terms of fuzzy boundaries. The model proposed here is consistent with all three of these interpretations.

1          Any observable phenomenon that can be dated has a natural temporal extent with fuzzy boundaries of gradual transition from not existing to definitely existing and then to no longer existing.

2          These fuzzy boundaries can also be interpreted as the time intervals about which experts, even with a complete knowledge of the described phenomenon, may not agree as to whether this phenomenon is already ongoing or not, or still ongoing or not.

3          Under a third interpretation, the fact that an instance of E2 Temporal Entity is ongoing is not observable within the fuzzy boundaries.

Consider, for instance, a birth. Extending over a limited and non-negligible duration in the scale of hours it begins and ends gradually (1), but can be given alternative scientific definitions of start and end points (2), and neither of these can be determined with a precision much smaller than on a scale of minutes (3). The fuzzy boundaries do not describe the relation of incomplete or imprecise knowledge to reality. Assuming a lowest granularity in time is an approach which does not help, because the relevant extent of fuzziness varies at a huge scale even in cultural reasoning, depending on the type of phenomena considered. The only exact match is between arbitrarily declared time intervals, such as the end of a year being equal to the beginning of the next year, or that “Early Minoan” ends exactly when “Middle Minoan” starts, whenever that might have been. Consequently, we introduce here a new set of “temporal relation primitives” with the following characteristics:

·     It is a minimal set of properties that allows for specifying all possible relations between two time intervals given by their start and end points, either directly, or by conjunction (logical AND condition) of the latter.

·     Start and end points are interpreted as “thick” fuzzy boundaries as described above.

·     Conditions of equality of end points are relaxed to the condition that the fuzzy boundaries overlap. Therefore, knowledge of the shape of the fuzzy function is not needed.

·     All of Allen’s relationships can be expressed either directly or by conjunctions of these properties.

·     In case of time intervals without or with negligibly short fuzzy boundaries, all of Allen’s relationships can exactly be described by adequate conjunctions of these properties.

·     No relationship is equal to the inverse of another. Inverses are specified by exchanging the roles of domain and range.

Notation

We use the following notation:

Comparing two instances of E2 Temporal Entity, we denote one with capital letter A, its (fuzzy) starting time with Astart and its (fuzzy) ending time with Aend, such that A = [Astart,Aend]; we denote the other with capital letter B, its (fuzzy) starting time with Bstart and its (fuzzy) ending time with Bend, such that B = [Bstart,Bend].

We identify a temporal relation with a predicate name (label) and define it by one or more (in)equality expressions between its end points, such as:

A starts before the end of B if and only if () Astart < Bend

We visualize a temporal relation symbolizing the temporal extents of two instances A and B of E2 Temporal Entity as horizontal bars, considered to be on a horizontal time-line proceeding from left to right. The fuzzy boundary areas are symbolized by an increasing/decreasing colour gradient. The different choices of relative arrangement the relationship allows for are symbolized by two extreme allowed positions of instance A with respect to instance B connected by arrows. The reader may imagine it as the relative positions of a train A approaching a station B. If the relative length of A compared to B matters, two diagrams are provided.

Key

1

Interior time points for which the described Temporal Entity is definitely on-going

2

Boundary fuzzy transitions zones in which the described Termporal Entity is developing or vanishing

3

A starts before the end of B

Figure 7: Explanation of Interior and Boundary and an Example of Use from P174 starts before the end of (ends after the start of).

Overview of Temporal Relation Primitives

The final set of temporal relation primitives can be separated into two groups:

1          Those based on improper inequalities, such as Astart ≤ Bend (odd number items in Table 2).

2          Those based on proper inequalities, such as Astart < Bend (even number items in Table 2).

Improper inequalities with fuzzy boundaries are understood as extending into situations in which the fuzzy boundaries of the respective endpoints may overlap. In other words, they include situations in which it cannot be decided when one interval has ended and when the other started, but there is no knowledge of a definite gap between these endpoints. In a proper inequality with fuzzy boundaries, the fuzzy boundaries of the respective endpoints must not overlap, i.e. there is knowledge of a definite gap between these endpoints, for instance, a discontinuity between settlement phases based on the observation of archaeological layers.

Table 2: Temporal Relation Primitives

 

Property

Interpretation

1

P173 starts before or with the end of

 

Astart ≤ Bend

2

P174 starts before the end of

Astart < Bend

 

3

P175 starts before or with the start of

Astart ≤ Bstart

 

4

P176 starts before the start of

Astart < Bstart

 

5

P182 ends before or with the start of

Aend ≤ Bstart

 

6

P183 ends before the start of

Aend < Bstart

 

7

P184 ends before or with the end of

Aend ≤ Bend

 

8

P185 ends before the end of

Aend < Bend

 

 


 

Class & Property Hierarchies

Although they do not provide comprehensive definitions, compact mono-hierarchical presentations of the class and property IsA hierarchies have been found to significantly aid comprehension and navigation of the CIDOC CRM. Since the CRM is poly-hierarchical, a mono-hierarchical presentation form is achieved by a top-down expansion of all inverse IsA relations regardless whether a concept has already be presented at another place in the same hierarchy. This form is provided below.

The class hierarchy presented below has the following format:

·     Each line begins with a unique class identifier, consisting of a number preceded by the letter “E” (originally denoting “entity,” although now replaced by convention with the term “class”).

·     A series of hyphens (“-”) follows the unique class identifier, indicating the hierarchical position of the class in the IsA hierarchy.

·     The English name of the class appears to the right of the hyphens.

·     The index is ordered by hierarchical level, in a “depth first” manner, from the smaller to the larger subhierarchies.

·     Classes that appear in more than one position in the class hierarchy as a result of multiple inheritance are shown in an italic typeface.

The property hierarchy presented below has the following format:

·     Each line begins with a unique property identifier, consisting of a number preceded by the letter “P” (for “property”).

·     A series of hyphens (“-”) follows the unique property identifier, indicating the hierarchical position of the property in the IsA hierarchy.

·     The English name of the property appears to the right of the hyphens, followed by its inverse name in parentheses for reading in the range to domain direction.

·     The domain class for which the property is declared.

·     The range class that the property references.

·     The index is ordered by hierarchical level, in a “depth first” manner, from the smaller to the larger subhierarchies, and by property number between equal siblings.

·     Properties that appear in more than one position in the property hierarchy as a result of multiple inheritance are shown in an italic typeface.

CIDOC CRM Class Hierarchy

Table 3: CIDOC CRM Class Hierarchy

E1

 CRM Entity

E2

-

 Temporal Entity

E3

-

-

Condition State

E4

-

-

Period

E5

-

-

-

Event

E7

-

-

-

-

Activity

E8

-

-

-

-

-

Acquisition

E96

-

-

-

-

-

-

Purchase

E9

-

-

-

-

-

Move

E10

-

-

-

-

-

Transfer of Custody

E11

-

-

-

-

-

Modification

E12

-

-

-

-

-

-

Production

E79

-

-

-

-

-

-

Part Addition

E80

-

-

-

-

-

-

Part Removal

E13

-

-

-

-

-

Attribute Assignment

E14

-

-

-

-

-

-

Condition Assessment

E15

-

-

-

-

-

-

Identifier Assignment

E16

-

-

-

-

-

-

Measurement

E17

-

-

-

-

-

-

Type Assignment

E65

-

-

-

-

-

Creation

E83

-

-

-

-

-

-

Type Creation

E66

-

-

-

-

-

Formation

E85

-

-

-

-

-

Joining

E86

-

-

-

-

-

Leaving

E87

-

-

-

-

-

Curation Activity

E63

-

-

-

-

Beginning of Existence

E67

-

-

-

-

-

Birth

E81

-

-

-

-

-

Transformation

E12

-

-

-

-

-

Production

E65

-

-

-

-

-

Creation

E83

-

-

-

-

-

-

Type Creation

E66

-

-

-

-

-

Formation

E64

-

-

-

-

End of Existence

E6

-

-

-

-

-

Destruction

E68

-

-

-

-

-

Dissolution

E69

-

-

-

-

-

Death

E81

-

-

-

-

-

Transformation

E77

-

Persistent Item

E70

-

-

Thing

E72

-

-

-

Legal Object

E18

-

-

-

-

Physical Thing

E19

-

-

-

-

-

Physical Object

E20

-

-

-

-

-

-

Biological Object

E21

-

-

-

-

-

-

-

Person

E22

-

-

-

-

-

-

Human-Made Object

E24

-

-

-

-

-

Physical Human-Made Thing

E22

-

-

-

-

-

-

Human-Made Object

E25

-

-

-

-

-

-

Human-Made Feature

E78

-

-

-

-

-

-

Curated Holding

E26

-

-

-

-

-

Physical Feature

E27

-

-

-

-

-

-

Site

E25

-

-

-

-

-

-

Human-Made Feature

E90

-

-

-

-

Symbolic Object

E73

-

-

-

-

-

Information Object

E29

-

-

-

-

-

 

Design or Procedure

E31

-

-

-

-

-

 

Document

E32

-

-

-

-

-

-

-

Authority Document

E33

-

-

-

-

-

-

Linguistic Object

E34

-

-

-

-

-

-

-

Inscription

E35

-

-

-

-

-

-

-

Title

E36

-

-

-

-

-

 

Visual Item

E37

-

-

-

-

-

-

-

Mark

E34

-

-

-

-

-

-

-

-

Inscription

E41

-

-

-

-

-

Appellation

E42

-

-

-

-

-

-

Identifier

E35

-

-

-

-

-

-

Title

E95

-

-

-

-

-

-

Spacetime Primitive

E94

-

-

-

-

-

-

Space Primitive

E61

-

-

-

-

-

-

Time Primitive

E71

-

-

-

Human-Made Thing

E24

-

-

-

-

Physical Human-Made Thing

E22

-

-

-

-

-

Human-Made Object

E25

-

-

-

-

-

Human-Made Feature

E78

-

-

-

-

-

Curated Holding

E28

-

-

-

-

Conceptual Object

E90

-

-

-

-

-

Symbolic Object

E73

-

-

-

-

-

-

Information Object

E29

-

-

-

-

-

-

-

Design or Procedure

E31

-

-

-

-

-

-

-

Document

E32

-

-

-

-

-

-

-

-

Authority Document

E33

-

-

-

-

-

-

 

Linguistic Object

E34

-

-

-

-

-

-

-

-

Inscription

E35

-

-

-

-

-

-

 

-

Title

E36

-

-

-

-

-

-

-

- Visual Item

E37

-

-

-

-

-

-

-

-

Mark

E34

-

-

-

-

-

-

-

-

-

Inscription

E41

-

-

-

-

-

-

Appellation

E42

-

-

-

-

-

-

-

Identifier

E35

-

-

-

-

-

-

-

Title

E95

-

-

-

-

-

-

-

Spacetime Primitive

E94

-

-

-

-

-

-

-

Space Primitive

E61

-

-

-

-

-

-

-

Time Primitive

E89

-

-

-

-

-

Propositional Object

E73

-

-

-

-

-

-

Information Object

E29

-

-

-

-

-

-

-

Design or Procedure

E31

-

-

-

-

-

-

-

Document

E32

-

-

-

-

-

-

-

-

Authority Document

E33

-

-

-

-

-

-

-

Linguistic Object

E34

-

-

-

-

-

-

-

-

Inscription

E35

-

-

-

-

-

-

-

-

Title

E36

-

-

-

-

-

-

-

Visual Item

E37

-

-

-

-

-

-

-

-

Mark

E34

-

-

-

-

-

-

-

-

-

Inscription

E30

-

-

-

-

-

-

Right

E55

-

-

-

-

-

Type

E56

-

-

-

-

-

-

Language

E57

-

-

-

-

-

-

Material

E58

-

-

-

-

-

-

Measurement Unit

E98

-

-

-

-

-

-

-

Currency

E99

-

-

-

-

-

-

Product Type

E39

-

-

Actor

E74

-

-

-

Group

E21

-

-

-

Person

E52

-

Time-Span

E53

-

Place

E54

-

Dimension

E97

-

-

Monetary Amount

E92

-

Spacetime Volume

E4

-

-

Period

E5

-

-

-

Event

E7

-

-

-

-

Activity

E8

-

-

-

-

-

Acquisition

E96

-

-

-

-

-

-

Purchase

E9

-

-

-

-

-

Move

E10

-

-

-

-

-

Transfer of Custody

E11

-

-

-

-

-

Modification

E12

-

-

-

-

-

-

Production

E79

-

-

-

-

-

-

Part Addition

E80

-

-

-

-

-

-

Part Removal

E13

-

-

-

-

-

Attribute Assignment

E14

-

-

-

-

-

-

Condition Assessment

E15

-

-

-

-

-

-

Identifier Assignment

E16

-

-

-

-

-

-

Measurement

E17

-

-

-

-

-

-

Type Assignment

E65

-

-

-

-

-

Creation

E83

-

-

-

-

-

-

Type Creation

E66

-

-

-

-

-

Formation

E85

-

-

-

-

-

Joining

E86

-

-

-

-

-

Leaving

E87

-

-

-

-

-

Curation Activity

E63

-

-

-

-

Beginning of Existence

E67

-

-

-

-

-

Birth

E81

-

-

-

-

-

Transformation

E12

-

-

-

-

-

Production

E65

-

-

-

-

-

Creation

E83

-

-

-

-

-

-

Type Creation

E66

-

-

-

-

-

Formation

E64

-

-

-

-

End of Existence

E6

-

-

-

-

-

Destruction

E68

-

-

-

-

-

Dissolution

E69

-

-

-

-

-

Death

E81

-

-

-

-

-

Transformation

E93

-

-

Presence

E59

-

Primitive Value

E60

-

-

Number

E61

-

-

Time Primitive

E62

-

-

String

E94

-

-

Space Primitive

E95

-

-

Spacetime Primitive



CIDOC CRM Property Hierarchy

Table 4: CIDOC CRM Property Hierarchy

Property id

Property Name

Entity – Domain

Entity - Range

P1

is identified by (identifies)

E1 CRM Entity

E41 Appellation

P48

   -   has preferred identifier (is preferred identifier of)

E1 CRM Entity

E42 Identifier

P102

   -   has title (is title of)

E71 Human-Made Thing

E35 Title

P168i

   -   place is defined by (defines place)

E53 Place

E94 Space primitive

P169i

   -   spacetime volume is defined by (defines spacetime volume)

E92 Spacetime Volume

E95 Spacetime Primitive

P170i

   -  time is defined by (defines time)

E52 Time-Span

E61 Time Primitive

P2

has type (is type of)

E1 CRM Entity

E55 Type

P137

   -   exemplifies (is exemplified by)

E1 CRM Entity

E55 Type

P177

   -   assigned property type

E13 Attribute Assignment

E55 Type

P3

has note

E1 CRM Entity

E62 String

P79

   -   beginning is qualified by

E52 Time-Span

E62 String

P80

   -   end is qualified by

E52 Time-Span

E62 String

P190

   -   has symbolic content

E90 Symbolic Object

E62 String

P4

has time-span (is time-span of)

E2 Temporal Entity

E52 Time-Span

P5

consists of (forms part of)

Å3 Condition State

Å3 Condition State

P7

took place at (witnessed)

E4 Period

E53 Place

P8

took place on or within (witnessed)

E4 Period

E18 Physical Thing

P12

occurred in the presence of (was present at)

E5 Event

E77 Persistent Item

P111

   -   added (was added by)

E79 Part Addition

E18 Physical Thing

P113

   -   removed (was removed by)

E80 Part Removal

E18 Physical Thing

P11

   -   had participant (participated in)

E5 Event

E39 Actor

P14

   -   -   carried out by (performed)

E7 Activity

E39 Actor

P22

   -   -   -   transferred title to (acquired title through)

E8 Acquisition

E39 Actor

P23

   -   -   -   transferred title from (surrendered title through)

E8 Acquisition

E39 Actor

P28

   -   -   -   custody surrendered by (surrendered custody through)

E10 Transfer of Custody

E39 Actor

P29

   -   -   -   custody received by (received custody through)

E10 Transfer of Custody

E39 Actor

P96

   -   -   by mother (gave birth)

E67 Birth

E21 Person

P99

   -   -   dissolved (was dissolved by)

E68 Dissolution

E74 Group

P143

   -   -   joined (was joined by)

E85 Joining

E39 Actor

P144

   -   -   joined with (gained member by)

E85 Joining

E74 Group

P145

   -   -   separated (left by)

E86 Leaving

E39 Actor

P146

   -   -   separated from (lost member by)

E86 Leaving

E74 Group

P151

   -   -   was formed from (participated  in)

E66 Formation

E74 Group

P16

   -   used specific object (was used for)

E7 Activity

E70 Thing

P33

   -   -   used specific technique (was used by)

E7 Activity

E29 Design or Procedure

P111

   -   -   added (was added by)

E79 Part Addition

E18 Physical Thing

P142

   -   -   used constituent (was used in)

E15 Identifier Assignment

E90 Symbolic Object

P25

   -   moved (moved by)

E9 Move

E19 Physical Object

P31

   -   has modified (was modified by)

E11 Modification

E18 Physical Thing

P108

   -  -    has produced (was produced by)

E12 Production

E24 Physical Human-Made Thing

P110

   -   -   augmented (was augmented by)

E79 Part Addition

E18 Physical Thing

P112

   -   -   diminished (was diminished by)

E80 Part Removal

E18 Physical Thing

P92

   -   brought into existence (was brought into existence by)

E63 Beginning of Existence

E77 Persistent Item

P94

   -   -   has created (was created by)

E65 Creation

E28 Conceptual Object

P135

   -   -   -   created type (was created by)

E83 Type Creation

E55 Type

P95

   -   -   has formed (was formed by)

E66 Formation

E74 Group

P98

   -   -   brought into life (was born)

E67 Birth

E21 Person

P108

   -  -    has produced (was produced by)

E12 Production

E24 Physical Human-Made Thing

P123

   -   -   resulted in (resulted from)

E81 Transformation

E77 Persistent Item

P93

   -   took out of existence (was taken out of existence by)

E64 End of Existence

E77 Persistent Item

P13

   -   -   destroyed (was destroyed by)

E6 Destruction

E18 Physical Thing

P99

   -   -   dissolved (was dissolved by)

E68 Dissolution

E74 Group

P100

   -   -   was death of (died in)

E69 Death

E21 Person

P124

   -   -   transformed (was transformed by)

E81 Transformation

E77 Persistent Item

P15

was influenced by (influenced)

E7 Activity

E1 CRM Entity

P16

   -   used specific object (was used for)

E7 Activity

E70 Thing

P33

   -   -   used specific technique (was used by)

E11 Modification

E29 Design or Procedure

P111

   -   -   added (was added by)

E79 Part Addition

E18 Physical Thing

P142

   -   -   used constituent (was used in)

E15 Identifier Assignment

E90 Symbolic Object

P17

   -   was motivated by (motivated)

E7 Activity

E1 CRM Entity

P134

   -   continued (was continued by)

E7 Activity

E7 Activity

P136

   -   was based on (supported type creation)

E83 Type Creation

E1 CRM Entity

P19

was intended use of (was made for)

E7 Activity

E71 Human-Made Thing

P20

had specific purpose (was purpose of)

E7 Activity

E5 Event

P21

had general purpose (was purpose of)

E7 Activity

E55 Type

P24

transferred title of (changed ownership through)

E8 Acquisition

E18 Physical Thing

P26

moved to (was destination of)

E9 Move

E53 Place

P27

moved from (was origin of)

E9 Move

E53 Place

P30

transferred custody of (custody transferred through)

E10 Transfer of Custody

E18 Physical Thing

P43

has dimension (is dimension of)

E70 Thing

E54 Dimension

P44

has condition (is condition of)

E18 Physical Thing

Å3 Condition State

P45

consists of (is incorporated in)

E18 Physical Thing

E57 Material

P49

has former or current keeper (is former or current keeper of)

E18 Physical Thing

E39 Actor

P50

   -   has current keeper (is current keeper of)

E18 Physical Thing

E39 Actor

P109

   -   has current or former curator (is current or former curator of)

E78 Curated Holding

E39 Actor

P51

has former or current owner (is former or current owner of)

E18 Physical Thing

E39 Actor

P52

   -   has current owner (is current owner of)

E18 Physical Thing

E39 Actor

P53

has former or current location (is former or current location of)

E18 Physical Thing

E53 Place

P55

   -   has current location (currently holds)

E19 Physical Object

E53 Place

P156

   -   occupies (is occupied by)

E18 Physical Thing

E53 Place

P54

has current permanent location (is current permanent location of)

E19 Physical Object

E53 Place

P57

has number of parts

E19 Physical Object

E60 Number

P59

has section (is located on or within)

E18 Physical Thing

E53 Place

P62

depicts (is depicted by)

E24 Physical Human-Made Thing

E1 CRM Entity

P67

refers to (is referred to by)

E89 Propositional Object

E1 CRM Entity

P68

   -   foresees use of (use foreseen by)

E29 Design or Procedure

E57 Material

P70

   -   documents (is documented in)

E31 Document

E1 CRM Entity

P71

   -   lists (is listed in)

E32 Authority Document

E1 CRM Entity

P129

   -   is about (is subject of)

E89 Propositional Object

E1 CRM Entity

P138

   -   represents (has representation)

E36 Visual Item

E1 CRM Entity

P69

has association with (is associated with)

E29 Design or Procedure

E29 Design or Procedure

P72

has language (is language of)

E33 Linguistic Object

E56 Language

P74

has current or former residence (is current or former residence of)

E39 Actor

E53 Place

P75

possesses (is possessed by)

E39 Actor

E30 Right

P76

has contact point (provides access to)

E39 Actor

E41 Appellation

P81

ongoing throughout

E52 Time-Span

E61 Time Primitive

P82

at some time within

E52 Time-Span

E61 Time Primitive

P86

falls within (contains)

E52 Time-Span

E52 Time-Span

P89

falls within (contains)

E53 Place

E53 Place

P90

has value

E54 Dimension

E60 Number

P91

has unit (is unit of)

E54 Dimension

E58 Measurement Unit

P180

   -   has currency

E97 Monetary Amount

E98 Currency

P97

from father (was father for)

E67 Birth

E21 Person

P101

had as general use (was use of)

E70 Thing

E55 Type

P103

was intended for (was intention of)

E71 Human-Made Thing

E55 Type

P104

is subject to (applies to)

E72 Legal Object

E30 Right

P105

right held by (has right on)

E72 Legal Object

E39 Actor

P52

   -   has current owner (is current owner of)

E18 Physical Thing

E39 Actor

P106

is composed of (forms part of)

E90 Symbolic Object

E90 Symbolic Object

P165

   -   incorporates (is incorporated in)

E73 Information Object

E90 Symbolic Object

P107

has current or former member (is current or former member of)

E74 Group

E39 Actor

P121

overlaps with

E53 Place

E53 Place

P122

borders with

E53 Place

E53 Place

P125

used object of type (was type of object used in)

E7 Activity

E55 Type

P32

   -   used general technique (was technique of)

E7 Activity

E55 Type

P126

employed (was employed in)

E11 Modification

E57 Material

P127

has broader term (has narrower term)

E55 Type

E55 Type

P130

shows features of (features are also found on)

E70 Thing

E70 Thing

P73i

   -   is translation of

E33 Linguistic Object

E33 Linguistic Object

P128

   -   carries (is carried by)

E18 Physical Thing

E90 Symbolic Object

P65

   -   -   shows visual item (is shown by)

E24 Physical Human-Made Thing

E36 Visual Item

P132

spatiotemporally overlaps with

E92 Spacetime Volume

E92 Spacetime Volume

P10

   -   falls within (contains)

E92 Spacetime Volume

E92 Spacetime Volume

P166

   -   -   was a presence of (had presence)

E93 Presence

E92 Spacetime Volume

P46

 is composed of (forms part of)

E18 Physical Thing

E18 Physical Thing

P56

    -   bears feature (is found on)

E19 Physical Object

E26 Physical Feature

P133

is separated from

E92 Spacetime Volume

E92 Spacetime Volume

P139

has alternative form (is alternative form of)

E41 Appellation

E41 Appellation

P140

assigned attribute to (was attributed by)

E13 Attribute Assignment

E1 CRM Entity

P34

   -   concerned (was assessed by)

E14 Condition Assessment

E18 Physical Thing

P39

   -   measured (was measured by)

E16 Measurement

E18 Physical Thing

P41

   -   classified (was classified by)

E17 Type Assignment

E1 CRM Entity

P141

assigned (was assigned by)

E13 Attribute Assignment

E1 CRM Entity

P35

   -   has identified (identified by)

E14 Condition Assessment

Å3 Condition State

P37

   -   assigned (was assigned by)

E15 Identifier Assignment

E42 Identifier

P38

   -   deassigned (was deassigned by)

E15 Identifier Assignment

E42 Identifier

P40

   -   observed dimension (was observed in)

E16 Measurement

E54 Dimension

P42

   -   assigned (was assigned by)

E17 Type Assignment

E55 Type

P147

curated (was curated by)

E87 Curation Activity

E78 Curated Holding

P148

has component (is component of)

E89 Propositional Object

E89 Propositional Object

P150

defines typical parts of (defines typical wholes for)

E55 Type

E55 Type

P152

has parent (is parent of)

E21 Person

E21 Person

P157

is at rest relative to (provides reference space for)

E53 Place

E18 Physical Thing

P59i

   -    is located on or within

E53 Place

E18 Physical Thing

P156i

   -    is occupied by

E53 Place

E18 Physical Thing

P160

has temporal projection

E92 Spacetime Volume

E52 Time-Span

P164

   -    is temporally specified by (temporally specifies)

E93 Presence

E52 Time-Span

P161

has spatial projection

E92 Spacetime Volume

E53 Place

P167

was within (includes)

E93 Presence

E53 Place

P171

at some place within

E53 Place

E94 Space Primitive

P172

contains

E53 Place

E94 Space Primitive

P173

starts before or with the end of (ends after or with the start of)

E2 Temporal Entity

E2 Temporal Entity

P174

   -   starts before the end of (ends after the start of)

E2 Temporal Entity

E2 Temporal Entity

P184

   -    -   ends before or with the end of (ends with or after the end of)

E2 Temporal Entity

E2 Temporal Entity

P185

   -    -   -   ends before the end of (ends after the end of)

E2 Temporal Entity

E2 Temporal Entity

P182

   -    -   -   -   ends before or with the start of (starts after or with the end of)

E2 Temporal Entity

E2 Temporal Entity

P175

   -    -   starts before or with the start of (starts after or with the start of)

E2 Temporal Entity

E2 Temporal Entity

P176

   -    -   -   starts before the start of (starts after the start of)

E2 Temporal Entity

E2 Temporal Entity

P134i

   -    -   -   -   was continued by

E7 Activity

E7 Activity

P182

   -    -   -   -   ends before or with the start of (starts after or with the end of)

E2 Temporal Entity

E2 Temporal Entity

P183

   -    -   -   -   -   ends before the start of (starts after the end of)

E2 Temporal Entity

E2 Temporal Entity

P179

had sales price (was sales price of)

E96 Purchase

E97 Monetary Amount

P186

produced thing of product type (is produced by)

E12 Production

E99 Product Type

P187

has production plan (is production plan for)

E99 Product Type

E29 Design or Procedure

P188

requires production tool (is production tool for)

E99 Product Type

E19 Physical Object

P189

approximates

E53 Place

E53 Place

P191

had duration (was duration of)

E52 Time-Span

E54 Dimension

P195

was a presence of (had presence)

E93 Presence

E18 Physical Thing

P196

defines (is defined by)

E18 Physical Thing

E92 Spacetime Volume

P197

covered parts of (was partially covered by)

E93 Presence

E53 Place

P198

holds or supports (is held or supported by)

E18 Physical Thing

E18 Physical Thing

 

 

CIDOC CRM Properties of Properties (.1 Properties)

 

Table 5: CIDOC CRM Properties of Properties (.1 Properties) Hierarchy

Property id

Property Name

Property – Domain

Entity - Range

P3.1

has type

E1 CRM Entity. P3 has note: E62 String

E55 Type

P14.1

in the role of

E7 Activity. P14 carried out by (performed):E39 Actor

E55 Type

P16.1

mode of use

E7 Activity. P16 used specific object (was used for): E70 Thing

E55 Type

P19.1

mode of use

E7 Activity. P19 was intended use of (was made for): E71 Human-Made Thing

E55 Type

P62.1

mode of depiction

E24 Physical Human-Made Thing. P62 depicts (is depicted by): E1 CRM Entity

E55 Type

P67.1

has type

E89 Propositional Object. P67 refers to (is referred to by): E1 CRM Entity

E55 Type

P138.1

   -   mode of representation

E36 Visual Item. P138 represents (has representation): E1 CRM Entity

E55 Type

P69.1

has type

E29 Design or Procedure. P69 has association with (is associated with): E29 Design or Procedure

E55 Type

P102.1

has type

E71 Human-Made Thing. P102 has title (is title of): E35 Title

E55 Type

P107.1

kind of member

E74 Group. P107 has current or former member (is current or former member of): E39 Actor

E55 Type

P136.1

in the taxonomic role

E83 Type Creation. P136 was based on (supported type creation): E1 CRM Entity

E55 Type

P130.1

kind of similarity

E70 Thing. P130 shows features of (features are also found on): E70 Thing.

E55 Type

P137.1

in the taxonomic role

E1 CRM Entity. P137 exemplifies (is exemplified by): E55 Type

E55 Type

P139.1

has type

E41 Appellation. P139 has alternative form (is alternative form of): E41 Appellation

E55 Type

P144.1

kind of member

E85 Joining.P144 joined with (gained member by): E74 Group

E55 Type

P189.1

has type

E53 Place. P189 approximates (is approximated by). E53 Place

E55 Type


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CIDOC CRM Class Declarations

The classes of the CIDOC CRM are comprehensively declared in this section using the following format:

·     Class names are presented as headings in bold face, preceded by the class’ unique identifier;

·     The line “Subclass of:” declares the superclass of the class from which it inherits properties;

·     The line “Superclass of:” is a cross-reference to the subclasses of this class;

·     The line “Scope note:” contains the textual definition of the concept the class represents;

·     The line “Examples:” contains a bulleted list of examples of instances of this class. If the example is also instance of a subclass of this class, the unique identifier of the subclass is added in parenthesis. If the example instantiates two classes, the unique identifiers of both classes is added in parenthesis. Non-fictitious examples may be followed by an explanation in brackets.

·     The line “In first-order logic:” expresses the formal constraints of the class in terms of logical axioms in a first-order logic notation;

·     The line “Properties:” declares the list of the class’ properties;

·     Each property is represented by its unique identifier, its forward and reverse names, and the range class that it links to, separated by colons;

·     Inherited properties are not represented;

·     Properties of properties are shown indented and in parentheses beneath their respective domain property.

 


 

E1 CRM Entity

Superclass of:      

E2 Temporal Entity

E52 Time-Span

E53 Place

E54 Dimension

E59 Primitive Value

E77 Persistent Item

E92 Spacetime Volume

Scope note:

This class comprises all things in the universe of discourse of the CIDOC Conceptual Reference Model.

It is an abstract concept providing for three general properties:

·         Identification by name or appellation, and in particular by a preferred identifier

·         Classification by type, allowing further refinement of the specific subclass to which an instance belongs

·         Attachment of free text and other unstructured data for the expression of anything not captured by formal properties

All other classes within the CIDOC CRM are directly or indirectly specialisations of E1 CRM Entity.

Examples:

  the earthquake in Lisbon 1755 (E5) (Chester, 2001)

In first-order logic:

E1(x)

Properties:

P1 is identified by (identifies): E41 Appellation

P2 has type (is type of): E55 Type

P3 has note: E62 String

(P3.1 has type: E55 Type)

P48 has preferred identifier (is preferred identifier of): E42 Identifier

P137 exemplifies (is exemplified by): E55 Type

(P137.1 in the taxonomic role: E55 Type)

E2 Temporal Entity

Subclass of:

Å1 CRM Entity

Superclass of:

Å3 Condition State

E4 Period

Scope note:

This class comprises all phenomena, such as the instances of E4 Periods and E5 Events, which happen over a limited extent in time. This extent in time must be contiguous, i.e., without gaps. In case the defining kinds of phenomena for an instance of E2 Temporal Entity cease to happen, and occur later again at another time, we regard that the former instance of E2 Temporal Entity has ended and a new instance has come into existence. In more intuitive terms, the same event cannot happen twice.

In some contexts, such phenomena are also called perdurants. This class is disjoint from E77 Persistent Item and is an abstract class that typically has no direct instances. E2 Temporal Entity is specialized into E4 Period, which applies to a particular geographic area (defined with a greater or lesser degree of precision), and E3 Condition State, which applies to instances of E18 Physical Thing.

Examples:

  Bronze Age (E4) (Childe, 1963)

  the earthquake in Lisbon 1755 (E5) (Chester, 2001)

  the Peterhof Palace near Saint Petersburg being in ruins from 1944 to 1946 (E3) (Maddox, 2015)

In first-order logic:

E2(x) E1(x)

Properties:

P4 has time-span (is time-span of): E52 Time-Span

P173 starts before or with the end of (ends after or with the start of): E2 Temporal Entity

P174 starts before the end of (ends after the start of): E2 Temporal Entity

P175 starts before or with the start of (starts after or with the start of): E2 Temporal Entity

P176 starts before the start of (starts after the start of): E2 Temporal Entity

P182 ends before or with the start of (starts after or with the end of): E2 Temporal Entity

P183 ends before the start of (starts after the end of): E2 Temporal Entity

P184 ends before or with the end of (ends with or after the end of): E2 Temporal Entity

P185 ends before the end of (ends after the end of): E2 Temporal Entity

E3 Condition State

Subclass of:

E2 Temporal Entity

Scope note:

This class comprises the states of objects characterised by a certain condition over a time-span.

An instance of this class describes the prevailing physical condition of any material object or feature during a specific instance of E52 Time-Span. In general, the time-span for which a certain condition can be asserted may be shorter than the real time-span, for which this condition held.

The nature of that condition can be described using P2 has type. For example, the instance of E3 Condition State “condition of the SS Great Britain between 22nd September 1846 and 27th August 1847” can be characterized as an instance “wrecked” of E55 Type.

Examples:

  the "reconstructed" state of the “Amber Room” in Tsarskoje Selo from summer 2003 until now (Owen, 2009)

  the "ruined" state of Peterhof Palace near Saint Petersburg from 1944 to 1946 (Maddox, 2015)

  the state of my turkey in the oven at 14:30 on 25th December 2002 [P2 has type: E55 Type “still not cooked”] (fictitious)

  the topography of the leaves of Sinai Printed Book 3234.2361 on the 10th July 2007 [described as: of type "cockled"] (fictitious)

In first-order logic:

E3(x) E2(x)

Properties:

P5 consists of (forms part of): Å3 Condition State

E4 Period

Subclass of:

E2 Temporal Entity

E92 Spacetime Volume

Superclass of:

E5 Event

Scope note:

This class comprises sets of coherent phenomena or cultural manifestations occurring in time and space.

It is the social or physical coherence of these phenomena that identify an instance of E4 Period and not the associated spatiotemporal extent. This extent is only the “ground” or space in an abstract physical sense that the actual process of growth, spread and retreat has covered. Consequently, different periods can overlap and coexist in time and space, such as when a nomadic culture exists in the same area and time as a sedentary culture. This also means that overlapping land use rights, common among first nations, amounts to overlapping periods.

Often, this class is used to describe prehistoric or historic periods such as the “Neolithic Period”, the “Ming Dynasty” or the “McCarthy Era”, but also geopolitical units and activities of settlements are regarded as special cases of E4 Period. However, there are no assumptions about the scale of the associated phenomena. In particular all events are seen as synthetic processes consisting of coherent phenomena. Therefore, E4 Period is a superclass of E5 Event. For example, a modern clinical birth, an instance of E67 Birth, can be seen as both a single event, i.e. an instance of E5 Event, and as an extended period, i.e. an instance of E4 Period, that consists of multiple physical processes and complementary activities performed by multiple instances of E39 Actor.

E4 Period is a subclass of E2 Temporal Entity and of E92 Spacetime Volume. The latter is intended as a phenomenal spacetime volume as defined in CIDOC CRMgeo (Doerr & Hiebel, 2013). By virtue of this multiple inheritance, it is possible to discuss the physical extent of an instance of E4 Period without representing each instance of it together with an instance of its associated spacetime volume. This model combines two quite different kinds of substance: an instance of E4 Period is a phenomenon while an instance of E92 Spacetime Volume is an aggregation of points in spacetime. However, the real spatiotemporal extent of an instance of E4 Period is regarded to be unique to it due to all its details and fuzziness; its identity and existence depends uniquely on the identity of the instance of E4 Period. Therefore, this multiple inheritance is unambiguous and effective and furthermore corresponds to the intuitions of natural language.

Typical use of this class in cultural heritage documentation is for documenting cultural and artistic periods. There are two different conceptualisations of ‘artistic style’, defined either by physical features or by historical context. For example, “Impressionism” can be viewed as a period in the European sphere of influence lasting from approximately 1870 to 1905 during which paintings with particular characteristics were produced by a group of artists that included (among others) Monet, Renoir, Pissarro, Sisley and Degas. Alternatively, it can be regarded as a style applicable to all paintings sharing the characteristics of the works produced by the Impressionist painters, regardless of historical context. The first interpretation is an instance of E4 Period, and the second defines morphological object types that fall under E55 Type.

A geopolitical unit as a specific case of an instance of E4 Period is the set of activities and phenomena related to the claim of power, the consequences of belonging to a jurisdictional area and an administrative system that establishes a geopolitical unit. Examples from the modern period are countries or administrative areas of countries such as districts whose actions and structures define activities and phenomena in the area that they intend to govern. The borders of geopolitical units are often defined in contracts or treaties although they may deviate from the actual practice. The spatiotemporal properties of Geopolitical units can be modelled through the properties inherited from E92 Spacetime Volume.

Another specific case of an instance of E4 Period is the actual extent of the set of activities and phenomena as evidenced by their physical traces that define a settlement, such as the populated period of Nineveh.

Examples:

  Jurassic (Hallam, 1975)

  Populated Period of Nineveh

  Imperial Rome under Marcus Aurelius

  European Bronze Age (Harrison, 2004)

  Italian Renaissance (Macdonald, 1992)

  Thirty Years War (Lee, 1991)

  Sturm und Drang (Berkoff, 2013)

  Cubism (Cox, 2000)

  The Capital of Russia (E4) [the capital of Russia in the sense of an administrative unit moved in historical times from Moscow to St Petersburg and then back to Moscow. This exemplifies an administrative unit changing place over time without temporal discontinuity]

  The settling activity of the community of Helsinki (a.k.a. Helsingfors) (E7) [the original settlement called Helsinki was located in the area of the modern airport. The community moved later to settle on the coast. This exemplifies a continued activity changing place over time without temporal discontinuity]

  Bronze Age (E4) [Bronze Age, in the sense of technological adoption, spread over disjoint areas including islands such as the British Isles without temporal discontinuity]

  Japan, the state (E4) [In 2021, the Japanese state as a political unit comprised in 6852 islands extending along the Pacific coast of Asia]

 

In first-order logic:

E4(x) E2(x)

E4(x) E92(x)

Properties:

P7 took place at (witnessed): E53 Place

P8 took place on or within (witnessed): E18 Physical Thing

P9 consists of (forms part of): E4 Period

E5 Event

Subclass of:

E4 Period

Superclass of:

E7 Activity

E63 Beginning of Existence

E64 End of Existence

Scope note:

This class comprises distinct, delimited and coherent processes and interactions of a material nature, in cultural, social or physical systems, involving and affecting instances of E77 Persistent Item in a way characteristic of the kind of process. Typical examples are meetings, births, deaths, actions of decision taking, making or inventing things, but also more complex and extended ones such as conferences, elections, building of a castle, or battles.

While the continuous growth of a tree lacks the limits characteristic of an event, its germination from a seed does qualify as an event. Similarly, the blowing of the wind lacks the distinctness and limits of an event, but a hurricane, flood or earthquake would qualify as an event. Mental processes are considered as events, in cases where they are connected with the material externalization of their results; for example, the creation of a poem, a performance or a change of intention that becomes obvious from subsequent actions or declarations.

The effects of an instance of E5 Event may not lead to relevant permanent changes of properties or relations of the items involved in it, for example an unrecorded performance. Of course, in order to be documented, some kind of evidence for an event must exist, be it witnesses, traces or products of the event.

While instances of E4 Period always require some form of coherence between its constituent phenomena, in addition, the essential constituents of instances of E5 Event should contribute to an overall effect; for example, the statements made during a meeting and the listening of the audience.

Viewed at a coarse level of detail, an instance of E5 Event may appear as if it had an ‘instantaneous’ overall effect, but any process or interaction of material nature in reality have an extent in time and space. At a fine level, instances of E5 Event may be analysed into component phenomena and phases within a space and timeframe, and as such can be seen as a period, regardless of the size of the phenomena. The reverse is not necessarily the case: not all instances of E4 Period give rise to a noteworthy overall effect and are thus not instances of E5 Event.

Examples:

  the birth of Cleopatra (E67) (Pomeroy, 1984)

  the destruction of Herculaneum by volcanic eruption in 79 AD (E6) (Camardo, 2013)

  World War II (E7) (Barber, 1994)

  the Battle of Stalingrad (E7) (Hoyt, 1993)

  the Yalta Conference (E7) (Harbutt, 2010)

  my birthday celebration 28-6-1995 (E7)

  the falling of a tile from my roof last Sunday (fictitious)

  the CIDOC conference 2003 (E7)

In first-order logic:

E5(x) E4(x)

Properties:

P11 had participant (participated in): E39 Actor

P12 occurred in the presence of (was present at): E77 Persistent Item

E6 Destruction

Subclass of:

E64 End of Existence

Scope note:

This class comprises events that destroy one or more instances of E18 Physical Thing, such that they lose their identity as the subjects of documentation.

Some destruction events are intentional, while others are independent of human activity. Intentional destruction can be documented by classifying the event as both an instance of E6 Destruction and of E7 Activity.

The decision to document an object as destroyed, transformed, or modified is context-sensitive:

1. If the matter remaining from the destruction is not documented, the event is modelled solely as an instance of E6 Destruction.

2. An event should also be documented using E81 Transformation if it results in the destruction of one or more objects and the simultaneous production of others using parts or material from the original. In this case, the new items have separate identities. Matter is preserved, but identity is not.

3. When the initial identity of the changed instance of E18 Physical Thing is preserved, the event should be documented as an instance of E11 Modification.

Examples:

  the destruction of Herculaneum by volcanic eruption in 79 AD (Camardo, 2013)

  the destruction of Nineveh (E6, E7) (River, 2016)

  the breaking of a champagne glass yesterday by my dog (fictitious)

In first-order logic:

E6(x) E64(x)

Properties:

P13 destroyed (was destroyed by): E18 Physical Thing

 

E7 Activity

Subclass of:

E5 Event

Superclass of:

E8 Acquisition

E9 Move

E10 Transfer of Custody

E11 Modification

E13 Attribute Assignment

E65 Creation

E66 Formation

E85 Joining

E86 Leaving

E87 Curation Activity

Scope note:

This class comprises actions intentionally carried out by instances of E39 Actor that result in changes of state in the cultural, social, or physical systems documented.

This notion includes complex, composite, and long-lasting actions such as the building of a settlement or a war, as well as simple, short-lived actions such as the opening of a door.

Examples:

  the Battle of Stalingrad (Hoyt, 1993)

  the Yalta Conference (Harbutt, 2010)

  my birthday celebration 28-6-1995

  the writing of “Faust” by Goethe (E65) (Williams, 2020)

  the formation of the Bauhaus 1919 (E66) (Droste, 2006)

  the people of Iraq giving the name ‘Quyunjig’ to the place identified by the TGN as ‘7017998’

  Kira Weber working in glass art from 1984 to 1993

  Kira Weber working in oil and pastel painting from 1993

In first-order logic:

E7(x) E5(x)

Properties:

P14 carried out by (performed): E39 Actor

(P14.1 in the role of: E55 Type)

P15 was influenced by (influenced): E1 CRM Entity

P16 used specific object (was used for): E70 Thing

(P16.1 mode of use: E55 Type)

P17 was motivated by (motivated): E1 CRM Entity

P19 was intended use of (was made for): E71 Human-Made Thing

(P19.1 mode of use: E55 Type)

P20 had specific purpose (was purpose of): E5 Event

P21 had general purpose (was purpose of): E55 Type

P32 used general technique (was technique of): E55 Type

P33 used specific technique (was used by): E29 Design or Procedure

P125 used object of type (was type of object used in): E55 Type

P134 continued (was continued by): E7 Activity

 

E8 Acquisition

Subclass of:

E7 Activity

Superclass of:

E96 Purchase

Scope note:

This class comprises transfers of legal ownership from one or more instances of E39 Actor to one or more other instances of E39 Actor.

The class also applies to the establishment or loss of ownership of instances of E18 Physical Thing. It does not, however, imply changes of any other kinds of rights. The recording of the donor and/or recipient is optional. It is possible that in an instance of E8 Acquisition there is either no donor or no recipient. Depending on the circumstances, it may describe:

1         the beginning of ownership

2         the end of ownership

3         the transfer of ownership

4         the acquisition from an unknown source

5         the loss of title due to destruction of the item

It may also describe events where a collector appropriates legal title, for example, by annexation or field collection. The interpretation of the museum notion of “accession” differs between institutions. The CIDOC CRM therefore models legal ownership (E8 Acquisition) and physical custody (E10 Transfer of Custody) separately. Institutions will then model their specific notions of accession and deaccession as combinations of these.

Examples

  the collection of a hammerhead shark, genus Sphyrna (Carchariniformes), by John Steinbeck and Edward Ricketts at Puerto Escondido in the Gulf of Mexico on 25th March 1940. (Steinbeck, 2000)

  the acquisition of El Greco’s “The Apostles Peter and Paul” by the State Hermitage in Saint Petersburg. (https://hermitagemuseum.org/wps/portal/hermitage/digital-collection/01.+Paintings/32730)

  the loss of my stuffed Fringilla coelebs due to insect damage last year (fictitious)

In first-order logic:

E8(x) E7(x)

Properties:

P22 transferred title to (acquired title through): E39 Actor

P23 transferred title from (surrendered title through): E39 Actor

P24 transferred title of (changed ownership through): E18 Physical Thing


 

E9 Move

Subclass of:

E7 Activity

Scope note:

This class comprises changes of the physical location of the instances of E19 Physical Object.

Note, that the class E9 Move inherits the property P7 took place at (witnessed): E53 Place. This property should be used to describe the trajectory or a larger area within which a move takes place, whereas the properties P26 moved to (was destination of), P27 moved from (was origin of) describe the start and end points only. Moves may also be documented to consist of other moves (via P9 consists of (forms part of)), in order to describe intermediate stages on a trajectory. In that case, start and end points of the partial moves should match appropriately between each other and with the overall event.

Examples:

  the relocation of London Bridge from the UK to the USA (Wildfang, 2005)

  the movement of the exhibition “Tutankhamun: Treasures of the Golden Pharaoh” between 15th September and 2nd November 2019

In first-order logic:

E9(x) E7(x)

Properties:

P25 moved (moved by): E19 Physical Object

P26 moved to (was destination of): E53 Place

P27 moved from (was origin of): E53 Place

E10 Transfer of Custody

Subclass of:

E7 Activity

Scope note:

This class comprises transfers of the physical custody or the legal responsibility for the physical custody of objects. The recording of the donor or recipient is optional. It is possible that in an instance of E10 Transfer of Custody there is either no donor or no recipient.

Depending on the circumstances, it may describe:

1         the beginning of custody (there is no previous custodian)

2         the end of custody (there is no subsequent custodian)

3         the transfer of custody (transfer from one custodian to the next)

4         the receipt of custody from an unknown source (the previous custodian is unknown)

5         the declared loss of an object (the current or subsequent custodian is unknown)

In the event that only a single kind of transfer of custody occurs, either the legal responsibility for the custody or the actual physical possession of the object but not both, this difference should be expressed using the property P2 has type (is type of).

The sense of physical possession requires that the object of custody be in the hands of the keeper at least with a part representative for the whole. The way, in which a representative part is defined, should ensure that it is unambiguous who keeps a part and who the whole and should be consistent with the identity criteria of the kept instance of E18 Physical Thing.

The interpretation of the museum notion of "accession" differs between institutions. The CIDOC CRM therefore models legal ownership and physical custody separately. Institutions will then model their specific notions of accession and deaccession as combinations of these.

Theft is a specific case of illegal transfer of custody.

Examples:

  the delivery of the paintings by Secure Deliveries Inc. to the National Gallery

  the return of Picasso’s “Guernica” to Madrid’s Prado in 1981 (Chipp, 1988)

  the transfer of custody of the work described as “Von der Velden ein Ufer an der See” from Johann Matthäus von Merian to the Auction House Heldevier (Jacob) for the purpose of sale, ca. 1716

  the transfer of custody of the painting ‘Mrs. Fitzherbert’ to the art dealer Knoedler from Parke-Bernet Galleries (New York, NY, USA) ca. March 1941

In first-order logic:

E10(x) E7(x)

Properties:

P28 custody surrendered by (surrendered custody through): E39 Actor

P29 custody received by (received custody through): E39 Actor

P30 transferred custody of (custody transferred through): E18 Physical Thing

 

E11 Modification

Subclass of:

E7 Activity

Superclass of:

E12 Production

E79 Part Addition

E80 Part Removal

Scope note:

This class comprises instances of E7 Activity that are undertaken to create, alter or change instances of E24 Physical Human-Made Thing.

This class includes the production of an item from raw materials and other so far undocumented objects. It also includes the conservation treatment of an object.

Since the distinction between modification and production is not always clear, modification is regarded as the more generally applicable concept. This implies that some items may be consumed or destroyed in an instance of E11 Modification, and that others may be produced as a result of it. An event should also be documented using an instance of E81 Transformation if it results in the destruction of one or more objects and the simultaneous production of others using parts or material from the originals. In this case, the new items have separate identities.

An activity undertaken on an object which was designed to alter it, but which, in fact, it did not in any seemingly significant way (such as the application of a solvent during conservation which failed to dissolve any part of the object), is still considered as an instance of E11 Modification. Typically, any such activity will leave at least forensic traces of evidence on the object.

If the instance of E29 Design or Procedure utilized for the modification prescribes the use of specific materials, they should be documented using property P68 foresees use of (use foreseen by): E57 Material of E29 Design or Procedure, rather than via P126 employed (was employed in): E57 Material.

Examples:

  the construction of the SS Great Britain (E12) (Gregor, 1971)

  the impregnation of the Vasa warship in Stockholm for preservation after 1956 (Håfors, 2010)

  the transformation of the Enola Gay into a museum exhibit by the National Air and Space Museum in Washington DC between 1993 and 1995 (E12, E81) (Yakel, 2000)

  the last renewal of the gold coating of the Toshogu shrine in Nikko, Japan (Cali and Dougil, 2012)

In first-order logic:

E11(x) E7(x)

Properties:

P31 has modified (was modified by): E18 Physical Thing

P126 employed (was employed in): E57 Material

E12 Production

Subclass of:

E11 Modification

E63 Beginning of Existence

Scope note:

This class comprises activities that are designed to, and succeed in, creating one or more new items.

It specializes the notion of modification into production. The decision as to whether or not an object is regarded as new is context sensitive. Normally, items are considered “new” if there is no obvious overall similarity between them and the consumed items and material used in their production. In other cases, an item is considered “new” because it becomes relevant to documentation by a modification. For example, the scribbling of a name on a potsherd may make it a voting token. The original potsherd may not be worth documenting, in contrast to the inscribed one.

This entity can be collective: the printing of a thousand books, for example, would normally be considered a single event.

An event should also be documented using an instance of E81 Transformation if it results in the destruction of one or more objects and the simultaneous production of others using parts or material from the originals. In this case, the new items have separate identities and matter is preserved, but identity is not.

Examples:

  the construction of the SS Great Britain (Gregor, 1971)

  the first casting of the Little Mermaid from the harbour of Copenhagen (Dewey, 2003)

  Rembrandt’s creating of the seventh state of his etching “Woman sitting half dressed beside a stove”, 1658, identified by Bartsch Number 197 (E12, E65, E81) (Hind, 1923)

In first-order logic:

E12(x) E11(x)

E12(x) E63(x)

Properties:

P108 has produced (was produced by): E24 Physical Human-Made Thing

P186 produced thing of product type (is produced by): E99 Product Type

E13 Attribute Assignment

Subclass of:

E7 Activity

Superclass of:

E14 Condition Assessment

E15 Identifier Assignment

E16 Measurement

E17 Type Assignment

Scope note:

This class comprises the actions of making assertions about one property of an object or any single relation between two items or concepts. The type of the property asserted to hold between two items or concepts can be described by the property P177 assigned property of type (is type of property assigned): E55 Type.

For example, the class describes the actions of people making propositions and statements during certain scientific/scholarly procedures, e.g. the person and date when a condition statement was made, an identifier was assigned, the museum object was measured, etc. Which kinds of such assignments and statements need to be documented explicitly in structures of a schema rather than free text, depends on whether this information should be accessible by structured queries.

This class allows for the documentation of how the respective assignment came about, and whose opinion it was. Note that all instances of properties described in a knowledge base are the opinion of someone. Per default, they are the opinion of the team maintaining the knowledge base. This fact must not individually be registered for all instances of properties provided by the maintaining team, because it would result in an endless recursion of whose opinion was the description of an opinion. Therefore, the use of instances of E13 Attribute Assignment marks the fact that the maintaining team is in general neutral to the validity of the respective assertion, but registers someone else’s opinion and how it came about.

All properties assigned in such an action can also be seen as directly relating the respective pair of items or concepts. Multiple use of instances of E13 Attribute Assignment may possibly lead to a collection of contradictory values.

Examples:

  the examination of MS Sinai Greek 418 by Nicholas Pickwoad in November 2003 (Honey & Pickwoad, 2010)

  the assessment of the current ownership of Martin Doerr’s silver cup in February 1997 (fictitious)

In first-order logic:

E13(x) E7(x)

Properties:

P140 assigned attribute to (was attributed by): E1 CRM Entity

P141 assigned (was assigned by): E1 CRM Entity

P177 assigned property type (is type of property assigned): E55 Type

E14 Condition Assessment

Subclass of:

E13 Attribute Assignment

Scope note:

This class describes the act of assessing the state of preservation of an object during a particular period.

The condition assessment may be carried out by inspection, measurement, or through historical research. This class is used to document circumstances of the respective assessment that is relevant to interpret its quality at a later stage, or to continue research on related documents.

Examples:

  last year’s inspection of humidity damage to the frescos in the St. George chapel in our village (fictitious)

  the condition assessment of the endband cores of MS Sinai Greek 418 by Nicholas Pickwoad in November 2003 (Honey & Pickwoad, 2010)

  the condition assessment of the cover of MS Sinai Greek 418 by Nicholas Pickwoad in November 2003 (Honey & Pickwoad, 2010)

In first-order logic:

E14(x) E13(x)

Properties:

P34 concerned (was assessed by): E18 Physical Thing

P35 has identified (was identified by): Å3 Condition State

E15 Identifier Assignment

Subclass of:

E13 Attribute Assignment

Scope note:

This class comprises activities that result in the allocation of an identifier to an instance of E1 CRM Entity. An instance of E15 Identifier Assignment may include the creation of the identifier from multiple constituents, which themselves may be instances of E41 Appellation. The syntax and kinds of constituents to be used may be declared in a rule constituting an instance of E29 Design or Procedure.

Examples of such identifiers include Find Numbers, Inventory Numbers, uniform titles in the sense of librarianship and Digital Object Identifiers (DOI). Documenting the act of identifier assignment and deassignment is especially useful when objects change custody or the identification system of an organization is changed. In order to keep track of the identity of things in such cases, it is important to document by whom, when, and for what purpose an identifier is assigned to an item.

The fact that an identifier is a preferred one for an organisation can be expressed by using the property E1 CRM Entity. P48 has preferred identifier (is preferred identifier of): E42 Identifier. It can better be expressed in a context independent form by assigning a suitable E55 Type, such as “preferred identifier assignment”, to the respective instance of E15 Identifier Assignment through the P2 has type (is type of) property.

Examples:

  replacement of the inventory number TA959a by GE34604 for a 17th century lamentation cloth at the Museum Benaki, Athens

  assigning the author and uniform title heading “Goethe, Johann Wolfgang von, 1749-1832. Faust. 1. Theil.” to a work

  on 1st June 2001, assigning the personal name heading “Guillaume, de Machaut, ca. 1300-1377” to Guillaume de Machaut (Kelly, 2014)

In first-order logic:

E15(x) E13(x)

Properties:

P37 assigned (was assigned by): E42 Identifier

P38 deassigned (was deassigned by): E42 Identifier

P142 used constituent (was used in): E90 Symbolic Object

E16 Measurement

Subclass of:

E13 Attribute Assignment

Scope note:

This class comprises actions measuring physical properties and other values that can be determined by a systematic, objective procedure of direct observation of particular states of physical reality.

An instance of E16 Measurement may use simple counting or tools, such as yardsticks or radiation detection devices. The interest is in the method and care applied, so that the reliability of the result may be judged at a later stage, or research continued on the associated documents. The date of the event is important for dimensions, which may change value over time, such as the length of an object subject to shrinkage. Methods and devices employed should be associated with instances of E16 Measurement by properties such as P33 used specific technique: E29 Design or Procedure, P125 used object of type: E55 Type, P16 used specific object (was used for): E70 Thing, whereas basic techniques such as "carbon-14 dating" should be encoded using P2 has type (is type of): E55 Type. Details of methods and devices reused or reusable in other instances of E16 Measurement should be documented for these entities rather than the measurements themselves, whereas details of particular execution may be documented by free text or by instantiating adequate sub-activities, if the detail may be of interest for an overarching query.

Regardless whether a measurement is made by an instrument or by human senses, it represents the initial transition from physical reality to information without any other documented information object in between within the reasoning chain that would represent the result of the interaction of the observer or device with reality. Therefore, determining properties of an instance of E90 Symbolic Object is regarded as an instance of E13 Attribute Assignment, which may be inferred from observing and measuring representative carriers. In the case that the carrier can be named, the property P16 used specific object (was used for) should be used to indicate the instance(s) of E18 Physical Thing that was used as the empirical basis for the attribute assignment. For instance, inferring properties of depicted items using image material, such as satellite images, is not regarded as an instance of E16 Measurement, but as a subsequent instance of E13 Attribute Assignment. Rather, only the production of the images, understood as arrays of radiation intensities, is regarded as an instance of E16 Measurement. The same reasoning holds for other sensor data.

Examples:

  measurement of the height of silver cup 232 on 31st August 1997 (fictitious)

  the carbon 14 dating of the “Schoeninger Speer II” in 1996 [The carbon 14 dating of an approximately 400.000 year old complete Old Palaeolithic wooden spear found in Schoeningen, Niedersachsen, Germany, in 1995.] (Kouwenhoven, 1997)

In first-order logic:

E16(x) E13(x)

Properties:

P39 measured (was measured by): E18 Physical Thing

P40 observed dimension (was observed in): E54 Dimension

E17 Type Assignment

Subclass of:

E13 Attribute Assignment

Scope note:

This class comprises the actions of classifying items of whatever kind. Such items include objects, specimens, people, actions, and concepts.

This class allows for the documentation of the context of classification acts in cases where the value of the classification depends on the personal opinion of the classifier, and the date that the classification was made. This class also encompasses the notion of “determination,” i.e. the systematic and molecular identification of a specimen in biology.

Examples:

  the first classification of object GE34604 as Lamentation cloth at the Museum Benaki, Athens

  the determination of a cactus in Martin Doerr’s garden as Cereus hildmannianus K.Schum., July 2003

In first-order logic:

E17(x) E13(x)

Properties:

P41 classified (was classified by): E1 CRM Entity

P42 assigned (was assigned by): E55 Type

E18 Physical Thing

Subclass of:

E72 Legal Object

Superclass of:

E19 Physical Object

E24 Physical Human-Made Thing

E26 Physical Feature

Scope note:

This class comprises all persistent physical items with a relatively stable form, human-made or natural.

Depending on the existence of natural boundaries of such things, the CIDOC CRM distinguishes the instances of E19 Physical Object from instances of E26 Physical Feature, such as holes, rivers, pieces of land, etc. Most instances of E19 Physical Object can be moved (if not too heavy), whereas features are integral to the surrounding matter.

An instance of E18 Physical Thing occupies not only a particular geometric space at any instant of its existence, but in the course of its existence it also forms a trajectory through spacetime, which occupies a real, that is phenomenal, volume in spacetime. We include in the occupied space the space filled by the matter of the physical thing and all its inner spaces, such as the interior of a box. For the purpose of more detailed descriptions of the presence of an instance of E18 Physical Thing in space and time it can be associated with its specific instance of E92 Spacetime Volume by the property P196 defines (is defined by).

The CIDOC CRM is generally not concerned with amounts of matter in fluid or gaseous states, as long as they are not confined in an identifiable way for an identifiable minimal time-span.

Examples:

  the Cullinan Diamond (E19) (Scarratt and Shor, 2006)

  the cave “Ideon Andron” in Crete (E26) (Smith, 1844-49)

  the Mona Lisa (E22) (Mohen, 2006)

In first-order logic:

E18(x) E72(x)

Properties:

P44 has condition (is condition of): Å3 Condition State

P45 consists of (is incorporated in): E57 Material

P46 is composed of (forms part of): E18 Physical Thing

P49 has former or current keeper (is former or current keeper of): E39 Actor

P50 has current keeper (is current keeper of): E39 Actor

P51 has former or current owner (is former or current owner of): E39 Actor

P52 has current owner (is current owner of): E39 Actor

P53 has former or current location (is former or current location of): E53 Place

P59 has section (is located on or within): E53 Place

P128 carries (is carried by): E90 Symbolic Object

P156 occupies (is occupied by): E53 Place

P196 defines (is defined by): E92 Spacetime Volume

E19 Physical Object

Subclass of:

E18 Physical Thing

Superclass of:

E20 Biological Object

E22 Human-Made Object

Scope note:

This class comprises items of a material nature that are units for documentation and have physical boundaries that separate them completely in an objective way from other objects.

The class also includes all aggregates of objects made for functional purposes of whatever kind, independent of physical coherence, such as a set of chessmen. Typically, instances of E19 Physical Object can be moved (if not too heavy).

In some contexts, such objects, except for aggregates, are also called “bona fide objects”, i.e. naturally defined objects (Smith & Varzi, 2000).

The decision as to what is documented as a complete item, rather than by its parts or components, may be purely administrative or may be a result of the order in which the item was acquired.

Examples:

  Aphrodite of Milos (E22) (Kousser, 2005)

  the Cullinan Diamond (Scarratt and Shor, 2006)

  Apollo 13 at the time of launch (E22) (Lovell and Kluger, 1994)

In first-order logic:

E19(x) E18(x)

Properties:

P54 has current permanent location (is current permanent location of): E53 Place

P55 has current location (currently holds): E53 Place

P56 bears feature (is found on): E26 Physical Feature

P57 has number of parts: E60 Number

E20 Biological Object

Subclass of:

E19 Physical Object

Superclass of:

E21 Person

Scope note:

This class comprises individual items of a material nature, which live, have lived, or are natural products of or from living organisms.

Artificial objects that incorporate biological elements, such as Victorian butterfly frames, can be documented as both instances of E20 Biological Object and E22 Human-Made Object.

Examples:

  me (fictitious)

  Tut-Ankh-Amun (Edwards and Boltin, 1979)

  Boukephalus [Horse of Alexander the Great] (Lamb, 2005)

  petrified dinosaur excrement PA1906-344

In first-order logic:

E20(x) E19(x)

E21 Person

Subclass of:

E20 Biological Object

E39 Actor

Scope note:

This class comprises real persons who live or are assumed to have lived.

Legendary figures that may have existed, such as Ulysses and King Arthur, fall into this class if the documentation refers to them as historical figures. In cases where doubt exists as to whether several persons are in fact identical, multiple instances can be created and linked to indicate their relationship. The CIDOC CRM does not propose a specific form to support reasoning about possible identity.

In a bibliographic context, a name presented following the conventions usually employed for personal names will be assumed to correspond to an actual real person (an instance of E21 Person), unless evidence is available to indicate that this is not the case. The fact that a persona may erroneously be classified as an instance of E21 Person does not imply that the concept comprises personae.

Examples:

  Tut-Ankh-Amun (Edwards and Boltin, 1979)

  Nelson Mandela (Brown and Hort, 2006)

In first-order logic:

E21(x) E20(x)

E21(x) E39(x)

Properties:

P152 has parent (is parent of): E21 Person

E22 Human-Made Object

Subclass of:  

E19 Physical Object

E24 Physical Human-Made Thing

Scope note:

This class comprises all persistent physical objects of any size that are purposely created by human activity and have physical boundaries that separate them completely in an objective way from other objects.

The class also includes all aggregates of objects made for functional purposes of whatever kind, independent of physical coherence, such as a set of chessmen.

Examples:

  the Rosetta Stone (E22)

  LNER Class A4 4468 Mallard [the World’s fastest steam locomotive, preserved at the National Railway Museum of York, UK] (Solomon, 2003)

  the Portland Vase (Walker, 2004)

In first-order logic:

E22(x) E19(x)

E22(x) E24(x)

E24 Physical Human-Made Thing

Subclass of:  

E18 Physical Thing

E71 Human-Made Thing

Superclass of:

E22 Human-Made Object

E25 Human-Made Feature

E78 Curated Holding

Scope note:

This class comprises all persistent physical items of any size that are purposely created by human activity. This class comprises, besides others, human-made objects, such as a sword, and human-made features, such as rock art. For example, a “cup and ring” carving on bedrock is regarded as instance of E24 Physical Human-Made Thing.

Instances of E24 Physical Human-Made Thing may be the result of modifying pre-existing physical things, preserving larger parts or most of the original matter and structure, which poses the question if they are new or even human-made, the respective interventions of production made on such original material should be obvious and sufficient to regard that the product has a new, distinct identity and intended function and is human-made. Substantial continuity of the previous matter and structure in the new product can be documented by describing the production process also as an instance of E81 Transformation.

Whereas interventions of conservation and repair are not regarded to produce a new instance of E24 Physical Human-Made Thing, the results of preparation of natural history specimens that substantially change their natural or original state should be regarded as instances of E24 Physical Human-Made Things, including the uncovering of petrified biological features from a solid piece of stone. On the other side, scribbling a museum number on a natural object should not be regarded to make it human-made. This notwithstanding, parts, sections, segments, or features of an instance of E24 Physical Human-Made Thing may continue to be non-human-made and preserved during the production process, for example natural pearls used as a part of an eardrop.

Examples:

  the Forth Railway Bridge (Shipway, Bouch, Baker and Fowler, 1990).

  the Channel Tunnel (E25) (Holliday, Marcou and Vickerman, 1991)

  the Palace of Knossos (Evans, 1921)

  the Colosseum in Rome, Italy (Hopkins and Beard, 2011)

  the Historical Collection of the Museum Benaki in Athens (E78) (Georgoula, 2005)

  the Rosetta Stone (E22)

  my paperback copy of Crime & Punishment (E22) (fictitious)

  the computer disk at ICS-FORTH that stores the canonical Definition of the CIDOC CRM v.3.2 (E22)

  my empty DVD disk (E22) (fictitious)

In first-order logic:

E24(x) E18(x)

E24(x) E71(x)

Properties:

P62 depicts (is depicted by): E1 CRM Entity

(P62.1 mode of depiction: E55 Type)

P65 shows visual item (is shown by): E36 Visual Item

E25 Human-Made Feature

Subclass of:  

E24 Physical Human-Made Thing

E26 Physical Feature

Scope note:

This class comprises physical features that are purposely created by human activity, such as scratches, artificial caves, artificial water channels, etc. In particular, it includes the information encoding features on mechanical or digital carriers.

 Examples:

 

  the Manchester Ship Canal (Farnie, 1980)

  Michael Jackson’s nose following plastic surgery

  the laser-readable “pits” engraved June 2014 on Martin Doerr’s CD-R, copying songs of Edith Piaf

  the carved letters on the Rosetta Stone

In first-order logic:

E25(x) E24(x)

E25(x) E26(x)

E26 Physical Feature

Subclass of:  

E18 Physical Thing

Superclass of:

E25 Human-Made Feature

E27 Site

Scope note:

This class comprises identifiable features that are physically attached in an integral way to particular physical objects.

Instances of E26 Physical Feature share many of the attributes of instances of E19 Physical Object. They may have a one-dimensional, two-dimensional, or three-dimensional geometric extent, but there are no natural borders that separate them completely in an objective way from the carrier objects. For example, a doorway is a feature but the door itself, being attached by hinges, is not.

Instances of E26 Physical Feature can be features in a narrower sense, such as scratches, holes, reliefs, surface colours, reflection zones in an opal crystal or a density change in a piece of wood. In the wider sense, they are portions of particular objects with partially imaginary borders, such as the core of the Earth, an area of property on the surface of the Earth, a landscape or the head of a contiguous marble statue. They can be measured and dated, and it is sometimes possible to state who or what is or was responsible for them. They cannot be separated from the carrier object, but a segment of the carrier object may be identified (or sometimes removed) carrying the complete feature.

This definition coincides with the definition of “fiat objects”, with the exception of aggregates of “bona fide objects” (Smith & Varzi, 2000).

Examples:

  the cave of Dirou, Mani, Greece (Psimenos. 2005)

  the temple in Abu Simbel before its removal, which was carved out of solid rock (E25) (Hawass, 2000)

  Albrecht Duerer's signature on his painting of Charles the Great (E25) (Strauss, 1974)

  the damage to the nose of the Great Sphinx in Giza (Temple, 2009)

  Michael Jackson’s nose prior to plastic surgery

In first-order logic:

E26(x) E18(x)

E27 Site

Subclass of:

E26 Physical Feature

Scope note:

This class comprises pieces of land or sea floor.

In contrast to the purely geometric notion of E53 Place, this class describes constellations of matter on the surface of the Earth or other celestial body, which can be represented by photographs, paintings, and maps.

Instances of E27 Site are composed of relatively immobile material items and features in a particular configuration at a particular location.

Examples:

  the Amazon river basin (Hegen, 1966)

  Knossos (Evans, 1921)

  the Apollo 11 landing site (Siegler and Smrekar, 2014)

  Heathrow Airport (Wicks, 2014)

  the submerged harbour of the Minoan settlement of Gournia, Crete (Watrous, 2012)

  the island of Crete

In first-order logic:

E27(x) E26(x)

E28 Conceptual Object

Subclass of:

E71 Human-Made Thing

Superclass of:

E55 Type

E89 Propositional Object

E90 Symbolic Object

Scope note:

This class comprises non-material products of our minds and other human produced data that have become objects of a discourse about their identity, circumstances of creation, or historical implication. The production of such information might have been supported by the use of technical devices such as cameras or computers.

Characteristically, instances of this class are created, invented or thought by someone, and then may be documented or communicated between persons. Instances of E28 Conceptual Object have the ability to exist on more than one particular carrier at the same time, such as paper, electronic signals, marks, audio media, paintings, photos, human memories, etc.

They cannot be destroyed. They exist as long as they can be found on at least one carrier or in at least one human memory. Their existence ends when the last carrier and the last memory are lost.

Examples:

  Beethoven’s “Ode an die Freude” (Ode to Joy) (E73) (Kershaw, 1999)

  the definition of “ontology” in the Oxford English Dictionary (E73) (Oxford University Press, 1989)

  the knowledge about the victory at Marathon carried by the famous runner (E89) (Lagos & Karyanos, 2020)

 

[Explanation note: The following examples illustrate the distinction between a propositional object, its names and its encoded forms. The Maxwell equations (Ball, 1962) are a good example, because they belong to the fundamental laws of physics and their mathematical content yields identical, unambiguous results regardless formulation and encoding.]

  “Maxwell equations” (E41) [preferred subject access point from LCSH, http://lccn.loc.gov/sh85082387, accessed 18th April 2021. This is only the name for the Maxwell equations as standardized by the Library of Congress and not the equations themselves.]

  “Equations, Maxwell” (E41) [variant subject access point from LCSH, http://lccn.loc.gov/sh85082387, accessed 18th April 2021. This is another name for the equation standardized by the Library of Congress and not the equations themselves.]

  Maxwell's equations (E89) [This is the propositional content of the equations proper, independent of any particular notation or mathematical formalism.] (Ball, 1962)

  The encoding of Maxwells equations as in https://upload.wikimedia.org/wikipedia/commons/c/c4/Maxwell%27sEquations.svg (E73) [accessed 18th April 2021. This is one possible symbolic encoding of the propositional content of the equations.]

In first-order logic:

E28(x) E71(x)

E29 Design or Procedure

Subclass of:

E73 Information Object

Scope note:

This class comprises documented plans for the execution of actions in order to achieve a result of a specific quality, form, or contents. In particular, it comprises plans for deliberate human activities that may result in new instances of E71 Human-Made Thing or for shaping or guiding the execution of an instance of E7 Activity.

Instances of E29 Design or Procedure can be structured in parts and sequences or depend on others.

This is modelled using P69 has association with (is associated with): E29 Design or Procedure.

Designs or procedures can be seen as one of the following:

1         A schema for the activities it describes

2         A schema of the products that result from their application

3         An independent intellectual product that may have never been applied, such as Leonardo da Vinci’s famous plans for flying machines

Because designs or procedures may never be applied or only partially executed, the CIDOC CRM models a loose relationship between the plan and the respective product.

Examples:

  the ISO standardisation procedure

  the musical notation for Beethoven’s “Ode to Joy” (Kershaw, 1999)

  the architectural drawings for the Kölner Dom (Cologne Cathedral) in Cologne, Germany (Wolff, 1999)

  the drawing found on Folio 860 of the Codex Atlanticus from Leonardo da Vinci, 1486 to 1490, kept in the Biblioteca Ambrosiana in Milan

In first-order logic:

E29(x) E73(x)

Properties:

P68 foresees use of (use foreseen by): E57 Material

P69 has association with (is associated with): E29 Design or Procedure

(P69.1 has type: E55 Type)

E30 Right

Subclass of:

E89 Propositional Object

Scope note:

This class comprises legal privileges concerning material and immaterial things or their derivatives.

These include reproduction and property rights.

Examples: 

  copyright held by ISO on ISO/CD 21127

  ownership of the “Mona Lisa” by the museum of the Louvre, Paris, France

 

In first-order logic:

E30(x) E89(x)

E31 Document

Subclass of:

E73 Information Object

Superclass of:

E32 Authority Document

Scope note:

This class comprises identifiable immaterial items that make propositions about reality.

These propositions may be expressed in text, graphics, images, audiograms, videograms, or by other similar means. Documentation databases are regarded as instances of E31 Document. This class should not be confused with the concept “document” in Information Technology, which is compatible with E73 Information Object.

Examples:

  the Encyclopaedia Britannica (E32) (Kogan, 1958)

  the image content of the photo of the Allied Leaders at Yalta published by UPI, 1945 (E36)

  Domesday Book [a manuscript record of the "Great Survey" of much of England and parts of Wales completed in 1086 by order of King William the Conqueror] (Hallam 1986)

In first-order logic:

E31(x) E73(x)

Properties:

P70 documents (is documented in): E1 CRM Entity

E32 Authority Document

Subclass of:

E31 Document

Scope note:

This class comprises encyclopaedia, thesauri, authority lists and other documents that define terminology or conceptual systems for consistent use.

Examples:

  Webster's Dictionary (Herbert, 1994)

  Getty Art and Architecture Thesaurus (Getty Trust, 1990)

  the CIDOC Conceptual Reference Model (Gergatsoulis et al., 2010) 

In first-order logic:

E32(x) E31(x)

Properties:

P71 lists (is listed in): E1 CRM Entity

E33 Linguistic Object

Subclass of:

E73 Information Object

Superclass of:

E34 Inscription

E35 Title

Scope note:

This class comprises identifiable expressions in natural language or languages.

Instances of E33 Linguistic Object can be expressed in many ways: e.g. as written texts, recorded speech, or sign language. However, the CIDOC CRM treats instances of E33 Linguistic Object independently from the medium or method by which they are expressed. Expressions in formal languages, such as computer code or mathematical formulae, are not treated as instances of E33 Linguistic Object by the CIDOC CRM. These should be modelled as instances of E73 Information Object.

In general, an instance of E33 Linguistic Object may also contain non-linguistic information, often of artistic or aesthetic value. Only in cases in which the content of an instance of E33 Linguistic Object can completely be expressed by a series of binary-encoded symbols, its content may be documented within a respective knowledge base by the property P190 has symbolic content: E62 String. Otherwise, it should be understood as an identifiable digital resource only available independently from the respective knowledge base.

In other cases, such as pages of an illuminated manuscript or recordings containing speech in a language supported by a writing system, the linguistic part of the content of an instance of E33 Linguistic Object may be documented within a respective knowledge base in a note by P3 has note: E62 String. Otherwise, it may be described using the property P165 incorporates (is incorporated in): E73 Information Object as a different object with its own identity.

Examples:

  the text of the Ellesmere Chaucer manuscript (Hilmo, 2019)

  the lyrics of the song “Blue Suede Shoes” (Cooper, 2008)

  the text of the “Jabberwocky” by Lewis Carroll (Carroll, 1981)

  the text of “Doktoro Jekyll kaj Sinjoro Hyde” [an Esperanto translation of Dr. Jekyll and Mr. Hyde]. (Stevenson, Morrison and Mann, 1909)

  the free dialog in the local dialect recorded in 1958, Telemark, Norway stored on tape or.7-89.s1 (00.15:46-00:34), The Language Collection at the University Library in Bergen, Norway (verified on 2020)

In first-order logic:

E33(x) E73(x)

Properties:

P72 has language (is language of): E56 Language

P73 has translation (is translation of): E33 Linguistic Object

E34 Inscription

Subclass of:

E33 Linguistic Object

E37 Mark

Scope note:

This class comprises recognisable texts that can be attached to instances of E24 Physical Human-Made Thing.

The transcription of the text can be documented in a note by P3 has note: E62 String. The alphabet used can be documented by P2 has type: E55 Type. This class is not intended to describe the idiosyncratic characteristics of an individual physical embodiment of an inscription, but the underlying prototype. The physical embodiment is modelled in the CIDOC CRM as instances of E24 Physical Human-Made Thing.

The relationship of a physical copy of a book to the text it contains is modelled using E18 Physical Thing. P128 carries (is carried by): E33 Linguistic Object.

Examples:

  “keep off the grass” [on a sign stuck in the lawn of the quad of Balliol College, Oxford, UK]

  the text published in Corpus Inscriptionum Latinarum V 895 (Mommsen, 1872)

  Kilroy was here”

In first-order logic:

E34(x) E33(x)

E34(x) E37(x)

E35 Title

Subclass of:

E33 Linguistic Object

E41 Appellation

Scope note:

This class comprises the textual strings that within a cultural context can be clearly identified as titles due to their form. Being a subclass of E41 Appellation, E35 Title can only be used when such a string is actually used as a title of a work, such as a text, an artwork, or a piece of music.

Titles are proper noun phrases or verbal phrases, and should not be confused with generic object names such as “chair”, “painting”, or “book” (the latter are common nouns that stand for instances of E55 Type). Titles may be assigned by the creator of the work itself, or by a social group.

This class also comprises the translations of titles that are used as surrogates for the original titles in different social contexts.

Examples:

  “The Merchant of Venice” (McCullough, 2005)

  “Mona Lisa” (Mohen, Menu and Mottin, 2006)

  “La Pie” (Bortolatto, 1981)

  “Lucy in the Sky with Diamonds” (Lennon, 1967)

In first-order logic:

E35(x) E33(x)

E35(x) E41(x)

E36 Visual Item

Subclass of:

E73 Information Object

Superclass of:

E37 Mark

Scope note:

This class comprises the intellectual or conceptual aspects of recognisable marks and images.

This class does not intend to describe the idiosyncratic characteristics of an individual physical embodiment of a visual item, but the underlying prototype. For example, a mark such as the ICOM logo is generally considered to be the same logo when used on any number of publications. The size, orientation, and colour may change, but the logo remains uniquely identifiable. The same is true of images that are reproduced many times. This means that visual items are independent of their physical support.

The E36 Visual Item class provides a means of identifying and linking together instances of E24 Physical Human-Made Thing that carry the same visual symbols, marks, or images, etc. The property P62 depicts (is depicted by) between E24 Physical Human-Made Thing and the depicted subjects (E1 CRM Entity) can be regarded as a shortcut of the more fully developed path from E24 Physical Human-Made Thing through P65 shows visual item (is shown by), E36 Visual Item, P138 represents (has representation) to E1 CRM Entity, which in addition captures the optical features of the depiction. 

Examples:

  the visual appearance of Monet’s “La Pie” (Bortolatto, 1981)

  the Coca-Cola logo (E34)

  the Chi-Rho (E37)

  the communist red star (E37)

  the surface shape of Auguste Rodin's statue "Le Penseur" [There exist more than 20 copies, even of different size. Therefore, this is a good example that it is only the common surface shape, an immaterial visual item, which justifies displaying these copies as works of Auguste Rodin. As usual practice, Rodin himself did not produce the bronze statue, but only the prototype model.]

In first-order logic:

E36(x) E73(x)

Properties:

P138 represents (has representation): E1 CRM Entity

(P138.1 mode of representation: E55 Type)

E37 Mark

Subclass of:

E36 Visual Item

Superclass of:

E34 Inscription

Scope note:

This class comprises symbols, signs, signatures, or short texts applied to instances of E24 Physical Human-Made Thing by arbitrary techniques, often in order to indicate such things as creator, owner, dedications, purpose, or to communicate information generally. Instances of E37 Mark do not represent the actual image of a mark, but the abstract ideal (or archetype) as used for codification in reference documents forming cultural documentation.

This class specifically excludes features that have no semantic significance, such as scratches or tool marks. These should be documented as instances of E25 Human-Made Feature.

Examples:

  Minoan double axe mark (Lowe Fri, 2011)

  ©

 

In first-order logic:

E37(x) E36(x)

E39 Actor

Subclass of:

E77 Persistent Item

Superclass of:

E21 Person

E74 Group

Scope note:

This class comprises people, either individually or in groups, who have the potential to perform intentional actions of kinds for which they can be held responsible.

Examples:

  London and Continental Railways (E74)

  the Governor of the Bank of England in 1975 (E21)

  Sir Ian McKellen (E21) (Gibson, 1986)

In first-order logic:

E39(x) E77(x)

Properties:

P74 has current or former residence (is current or former residence of): E53 Place

P75 possesses (is possessed by): E30 Right

P76 has contact point (provides access to): E41 Appellation

E41 Appellation

Subclass of:

E90 Symbolic Object

Superclass of:

E35 Title

E42 Identifier

E61 Time Primitive

E94 Space Primitive

E95 Spacetime Primitive

Scope note:

This class comprises all signs, either meaningful or not, or arrangements of signs following a specific syntax, that are used or can be used to refer to and identify a specific instance of some class within a certain context.

Instances of E41 Appellation do not identify things by their meaning, even if they happen to have one, but by convention, tradition, or agreement. Instances of E41 Appellation are cultural constructs; as such, they have a context, a history, and a use in time and space by some group of users. A given instance of E41 Appellation can have alternative forms, i.e. other instances of E41 Appellation that are regarded as equivalent, regardless of the thing it denotes.

Different languages may use different appellations for the same thing, such as the names of major cities. Some appellations may be formulated using a valid noun phrase of a particular language. In these cases, the respective instances of E41 Appellation should also be declared as instances of E33 Linguistic Object. Then the language using the appellation can be declared with the property P72 has language: E56 Language.

Instances of E41 Appellation may be used to identify any instance of E1 CRM Entity and sometimes are characteristic for instances of more specific subclasses of E1 CRM Entity, such as for instances of E52 Time-Span (for instance “dates”), E39 Actor, E53 Place or E28 Conceptual Object. Postal addresses and E-mail addresses are characteristic examples of identifiers used by services transporting things between clients.

Even numerically expressed identifiers for extents in space or time are also regarded as instances of E41 Appellation, such as Gregorian dates or spatial coordinates, even though they allow for determining some time or location by a known procedure starting from a reference point and by virtue of that fact play a double role as instances of E59 Primitive Value.

E41 Appellation should not be confused with the act of naming something. Cf. E15 Identifier Assignment.

Examples:

  “Martin”

  “Aquae Sulis Minerva”

  “the Merchant of Venice” (E35) (McCullough, 2005)

  “Spigelia marilandica (L.) L.” [not the species, just the name] (Hershberger, Robacker and Jenkins, 2015)

  “information science” [not the science itself, but the name used to refer to the subject matter in an English-speaking context]

  ” [Chinese “an”, meaning “peace”]

  “6°5’29”N 45°12’13”W” [example of a spatial coordinate]

  “Black queen’s bishop 4” [chess coordinate, example of an identifier in a conceptual space (E89)]

  “19-MAR-1922” [example of date]

  “+41 22 418 5571” [example of contact point]

  “weasel@paveprime.com” [example of contact point]

  “CH-1211, Genève” [example of place appellation]

  “1-29-3 Otsuka, Bunkyo-ku, Tokyo, 121, Japan” [example of a postal address]

  “the poop deck of H.M.S Victory” [example of a section definition on a human-made object (E22)]

  “the Venus de Milo’s left buttock” [example of a section definition on a human-made object (E22)]

In first-order logic:

E41(x) E90(x)

Properties:

P139 has alternative form (is alternative form of): E41 Appellation

(P139.1 has type: E55 Type)

E42 Identifier

Subclass of:

E41 Appellation

Scope note:

This class comprises strings or codes assigned to instances of E1 CRM Entity in order to identify them uniquely and permanently within the context of one or more organisations. Such codes are often known as inventory numbers, registration codes, etc. and are typically composed of alphanumeric sequences. Postal addresses, telephone numbers, URLs and e-mail addresses are characteristic examples of identifiers used by services transporting things between clients.

The class E42 Identifier is not normally used for machine-generated identifiers used for automated processing unless these are also used by human agents.

Examples:

  “MM.GE.195”

  “13.45.1976”

  “OXCMS: 1997.4.1” (fictitious)

  “ISSN 0041-5278” [Identifier for “The UNESCO Courier (Print)”]

  ISRC “FIFIN8900186” [Identifier for : Kraft (29 min 14 s) / Magnus Lindberg, comp. ; Toimii Ensemble ; Swedish Radio symphony orchestra ; Esa-Pekka Salonen, dir.]

  Shelf mark “Res 8 P 10”

  “Guillaume de Machaut (1300?-1377)” [a controlled personal name heading that follows the French rules] (Reaney, 1974)

  “+41 22 418 5571”

  weasel@paveprime.com

  “Rue David Dufour 5, CH-1211, Genève”

  “1-29-3 Otsuka, Bunkyo-ku, Tokyo, 121, Japan”

In first-order logic:

E42(x) E41(x)

E52 Time-Span

Subclass of:

E1 CRM Entity

Scope note:

This class comprises abstract temporal extents, in the sense of Galilean physics, having a beginning, an end, and a duration.

Instances of E52 Time-Span have no semantic connotations about phenomena happening within the temporal extent they represent. They do not convey any meaning other than a positioning on the “time-line” of chronology. The actual extent of an instance of E52 Time-Span can be approximated by properties of E52 Time-Span giving inner and outer bounds in the form of dates (instances of E61 Time Primitive). Comparing knowledge about time-spans is fundamental for chronological reasoning.

Some instances of E52 Time-Span may be defined as the actual, in principle observable, temporal extent of instances of E2 Temporal Entity via the property P4 has time-span (is time-span of): E52 Time-Span. They constitute phenomenal time-spans as defined in CRMgeo (Doerr & Hiebel 2013). Since our knowledge of history is imperfect and physical phenomena are fuzzy in nature, the extent of phenomenal time-spans can only be described in approximation. An extreme case of approximation, might, for example, define an instance of E52 Time-Span having unknown beginning, end and duration. It may, nevertheless, be associated with other descriptions by which people can infer knowledge about it, such as in relative chronologies.

Some instances of E52 may be defined precisely as representing a declaration of a temporal extent, as, for instance, done in a business contract. They constitute declarative time-spans as defined in CRMgeo (Doerr & Hiebel 2013) and can be described via the property E61 Time Primitive P170 defines time (time is defined by): E52 Time-Span.

When used as a common E52 Time-Span for two events, it will nevertheless describe them as being simultaneous, even if nothing else is known.

Examples:

  1961

  From 12-17-1993 to 12-8-1996

  14h30 to 16h22 4th July 1945

  9.30 am 1.1.1999 to 2.00 pm 1.1.1999

  the time-span of the Ming Dynasty (Chan, 2011)

In first-order logic:

E52(x) E1(x)

Properties:

P79 beginning is qualified by: E62 String

P80 end is qualified by: E62 String

P81 ongoing throughout: E61 Time Primitive

P82 at some time within: E61 Time Primitive

P86 falls within (contains): E52 Time-Span

P191 had duration (was duration of): E54 Dimension


 

E53 Place

Subclass of:

E1 CRM Entity

Scope note:

This class comprises extents in the natural space where people live, in particular on the surface of the Earth, in the pure sense of physics: independent from temporal phenomena and matter. They may serve describing the physical location of things or phenomena or other areas of interest. Geometrically, instances of E53 Place constitute single contiguous areas or a finite aggregation of disjoint areas in space which are each individually contiguous. They may have fuzzy boundaries.

The instances of E53 Place are usually determined by reference to the position of “immobile” objects such as buildings, cities, mountains, rivers, or dedicated geodetic marks, but may also be determined by reference to mobile objects. A Place can be determined by combining a frame of reference and a location with respect to this frame.

It is sometimes argued that instances of E53 Place are best identified by global coordinates or absolute reference systems. However, relative references are often more relevant in the context of cultural documentation and tend to be more precise. In particular, people are often interested in position in relation to large, mobile objects, such as ships. For example, the Place at which Nelson died is known with reference to a large mobile object, i.e. H.M.S Victory. A resolution of this Place in terms of absolute coordinates would require knowledge of the movements of the vessel and the precise time of death, either of which may be revised, and the result would lack historical and cultural relevance.

Any instance of E18 Physical Thing can serve as a frame of reference for an instance of E53 Place. This may be documented using the property P157 is at rest relative to (provides reference space for).

Examples:

  the extent of the UK in the year 2003

  the position of the hallmark on the inside of my wedding ring (fictitious)

  the place referred to in the phrase: “Fish collected at three miles north of the confluence of the Arve and the Rhone”

  here -> <- [the place between these two arrows in one of the reader's paper copy of this document. Each copy constitutes a different place of this spot.]

In first-order logic:

E53(x) E1(x)

Properties:

P89 falls within (contains): E53 Place

P121 overlaps with: E53 Place

P122 borders with: E53 Place

P157 is at rest relative to (provides reference space for): E18 Physical Thing

P168 place is defined by (defines place): E94 Space Primitive

P171 at some place within: E94 Space Primitive

P172 contains: E94 Space Primitive

P189 approximates (is approximated by): E53 Place

 

E54 Dimension

Subclass of:

E1 CRM Entity

Superclass of:

E97 Monetary Amount

Scope note:

This class comprises quantifiable properties that can be measured by some calibrated means and can be approximated by values, i.e. points or regions in a mathematical or conceptual space, such as natural or real numbers, RGB values, etc.

An instance of E54 Dimension represents the empirical or theoretically derived quantity, including the precision tolerances resulting from the particular method or calculation. The identity of an instance of E54 Dimension depends on the method of its determination because each method may produce different values even when determining comparable qualities. For instance, the wingspan of a bird alive or dead is a different dimension. Thermoluminescence dating and Rehydroxylation [RHX] dating are different dimensions of temporal distance from now, even if they aim at dating the same object. The method of determination should be expressed using the property P2 has type (is type of). Note that simple terms such as “diameter” or “length” are normally insufficient to unambiguously describe a respective dimension. In contrast, “maximum linear extent” may be sufficient.

The properties of the class E54 Dimension allow for expressing the numerical approximation of the values of instances of E54 Dimension adequate to the precision of the applied method of determination. If the respective quantity belongs to a non-discrete space according to the laws of physics, such as spatial distances, it is recommended to record them as approximations by intervals or regions of indeterminacy enclosing the assumed true values. For instance, a length of 5 cm may be recorded as 4.5-5.5 cm, according to the precision of the respective observation. Note, that comparability of values described in different units depends critically on the representation as value regions.

Numerical approximations in archaic instances of E58 Measurement Unit used in historical records should be preserved. Equivalents corresponding to current knowledge should be recorded as additional instances of E54 Dimension, as appropriate.

Examples:

  the weight of the Luxor Obelisk [250 metric tons]

  the vertical height of the statue of David by Michelangelo [5.17 metres]

  the weight of the Great Star of Africa diamond [530.2 carats]

  the calibrated C14 date for the Shroud of Turin [AD1262-1312, 1303-1384]

  the horizontal diameter of the Stonehenge Sarsen Circle [33 metres] (Pryor, 2016)

  the length of the sides of the Great Pyramid at Giza [230.34 metres] (Lehner and Hawass, 2017)

  the duration of the time-span of the Battle of Issos/Issus on 15th November 333 B.C.E. [less than 12 hours] (Howard, 2012)

  Christie’s hammer price, in British Pounds, for Vincent van Gogh's "Still Life: Vase with Fifteen Sunflowers" in London on 30th March 1987 (E97) [24.75 million GBP (British Pounds)]


 

In first-order logic:

E54(x) E1(x)

Properties:

P90 has value: E60 Number

P91 has unit (is unit of): E58 Measurement Unit

E55 Type

Subclass of:

E28 Conceptual Object

Superclass of:

E56 Language

E57 Material

E58 Measurement Unit

E99 Product Type

Scope note:

This class comprises concepts denoted by terms from thesauri and controlled vocabularies used to characterize and classify instances of CIDOC CRM classes. Instances of E55 Type represent concepts, in contrast to instances of E41 Appellation which are used to name instances of CIDOC CRM classes.

E55 Type provides an interface to domain specific ontologies and thesauri. These can be represented in the CIDOC CRM as subclasses of E55 Type, forming hierarchies of terms, i.e. instances of E55 Type linked via P127 has broader term (has narrower term): E55 Type. Such hierarchies may be extended with additional properties.

Examples:

  weight, length, depth [types for instances of E54 Dimension]

  portrait, sketch, animation [types for instances of E36 Visual Item]

  French, English, German [types for instances of E56 Language]

  excellent, good, poor [types for instances of E3 Condition State]

  Ford Model T, chop stick [types for instances of E22 Human-Made Object]

  cave, doline, scratch [types for instances of E26 Physical Feature]

  poem, short story [types for instances of E33 Linguistic Object]

  wedding, earthquake, skirmish [types for instances of E5 Event]

In first-order logic:

E55(x) E28(x)

Properties:

P127 has broader term (has narrower term): E55 Type

P150 defines typical parts of (define typical wholes for): E55 Type

E56 Language

Subclass of:

E55 Type

Scope note:

This class is a specialization of E55 Type and comprises the natural languages in the sense of concepts.

This type is used categorically in the model without reference to instances of it, i.e. the Model does not foresee the description of instances of instances of E56 Language, e.g. “instances of Mandarin Chinese”.

It is recommended that internationally or nationally agreed codes and terminology should be used to denote instances of E56 Language, such as those defined in ISO 639-3:2007 and later versions.

Examples:

  ell [Greek]

  eng [English]

  epo [Esperanto]

  spa [Spanish]

  fra [French]

In first-order logic:

E56(x) E55(x)

E57 Material

Subclass of:

E55 Type

Scope note:

This class is a specialization of E55 Type and comprises the concepts of materials.

Instances of E57 Material may denote properties of matter before its use, during its use, and as incorporated in an object, such as ultramarine powder, tempera paste, reinforced concrete. Discrete pieces of raw-materials kept in museums, such as bricks, sheets of fabric, pieces of metal, should be modelled individually in the same way as other objects. Discrete used or processed pieces, such as the stones from Nefer Titi's temple, should be modelled as parts (cf. P46 is composed of (forms part of): E18 Physical Thing).

This type is used categorically in the model without reference to instances of it, i.e. the Model does not foresee the description of instances of instances of E57 Material, e.g. “instances of gold”.

It is recommended that internationally or nationally agreed codes and terminology should be used.

Examples:

  brick (Gurcke, 1987)

  gold (Watson, 1990)

  aluminium (Norman, 1986)

  polycarbonate (Mhaske, 2011)

  resin (Barton, 1992)

In first-order logic:

E57(x) E55(x)

E58 Measurement Unit

Subclass of:

E55 Type

Superclass of:

E98 Currency

Scope note:

This class is a specialization of E55 Type and comprises the types of measurement units: feet, inches, centimetres, litres, lumens, etc.

This type is used categorically in the model without reference to instances of it, i.e. the model does not foresee the description of instances of instances of E58 Measurement Unit, e.g. “instances of cm”.

Système International (SI) units or internationally recognized non-SI terms should be used whenever possible, such as those defined by ISO80000:2009. Archaic Measurement Units used in historical records should be preserved.

Examples:

  cm [centimetre]

  km [kilometre]

  m [metre]

  m/s [metres per second] (Hau et al., 1999)

  A [ampere]

  GRD [Greek Drachma] (E98) (Daniel, 2014)

  °C [degrees centigrade] (Beckman, 1998)

In first-order logic:

E58(x) E55(x)

E59 Primitive Value

Subclass of:

E1 CRM Entity

Superclass of:

E60 Number

E61 Time Primitive

E62 String

E94 Space Primitive

E95 Spacetime Primitive

Scope note:

This class comprises values of primitive data types of programming languages or database management systems and data types composed of such values used as documentation elements, as well as their mathematical abstractions.

The instances of E59 Primitive Value and its subclasses are not considered elements of the universe of discourse the CIDOC CRM aims to define and analyse. Rather, they play the role of a symbolic interface between the scope of the model and the world of mathematical and computational manipulations and the symbolic objects they define and handle.

In particular, they comprise lexical forms encoded as “strings” or series of characters and symbols based on encoding schemes (characterised by being a limited subset of the respective mathematical abstractions) such as UNICODE and values of datatypes that can be encoded in a lexical form, including quantitative specifications of time-spans and geometry. They have in common that instances of E59 Primitive Value define themselves by virtue of their encoded value, regardless of the nature of their mathematical abstractions.

Therefore, in an implementation, instances of E59 Primitive should be represented directly in the encoded symbolic form supported by the respective platform, such as a character string or a formatted date. They must not be represented in an implementation indirectly via, another a universal resource identifier, which in turn is linked to the actual encoded symbolic form. In a concrete application, it is recommended that the primitive value system from a chosen implementation platform and/or data definition language be used to substitute for this class and its subclasses.

Examples:            

  “ABCDEFG” (E62)

  3.14 (E60)

  0 (E60)

  1921-01-01 (E61)

In first-order logic:

E59(x) E1(x)

E60 Number

Subclass of:

E59 Primitive Value

Scope note:

This class comprises any encoding of computable (algebraic) values such as integers, real numbers, complex numbers, vectors, tensors, etc., including intervals of these values to express limited precision.

Numbers are fundamentally distinct from identifiers in continua, which are instances of E41 Appellation, such as Gregorian dates or spatial coordinates, even though their encoding may be similar. Instances of E60 Number can be combined with each other in algebraic operations to yield other instances of E60 Number, e.g. 1 + 1 = 2. Identifiers in continua may be combined with numbers expressing distances to yield new identifiers, e.g., 1924-01-31 + 2 days = 1924-02-02. Cf. E54 Dimension.

Examples:

  5

  3+2i

  1.5e-04

  (0.5, - 0.7,88)

In first-order logic:

E60(x) E59(x)

E61 Time Primitive

Subclass of:

E41 Appellation

E59 Primitive Value

Scope note:

This class comprises instances of E59 Primitive Value for time that should be implemented with appropriate validation, precision, and references to temporal coordinate systems to express time in some context relevant to cultural and scientific documentation.

Instantiating different instances of E61 Time Primitive relative to the same instance of E52 Time-Span allows for the expression of multiple opinions/approximations of the same phenomenon. When representing different opinions/approximations of the E52 Time-Span of some E2 Temporal Entity, multiple instances of E61 Time Primitive should be instantiated relative to one E52 Time-Span. Only one E52 Time-Span should be instantiated since there is only one real phenomenal time extent of any given temporal entity.

The instances of E61 Time Primitive are not considered as elements of the universe of discourse that the CIDOC CRM aims at defining and analysing. Rather, they play the role of a symbolic interface between the scope of this model and the world of mathematical and computational manipulations and the symbolic objects they define and handle.

Therefore, they must not be represented in an implementation by a universal identifier associated with a content model of different identity. In a concrete application, it is recommended that the primitive value system from a chosen implementation platform and/or data definition language be used to substitute for this class.

Examples:

  “1994 to 1997”

  “13th May 1768”

  “2000/01/01 00:00:59.7”

  “85th century BCE”

In first-order logic:

E61(x) E41(x)

E61(x) E59(x)

Properties:

P170 defines time (time is defined by): E52 Time-Span

E62 String

Subclass of:

E59 Primitive Value

Scope note:

This class comprises coherent sequences of binary-encoded symbols. They correspond to the content of an instance of E90 Symbolic object. Instances of E62 String represent only the symbol sequence itself. They may or may not contain a language code.

In contrast, instances of other subclasses of E59 Primitive value represent entities in mathematical spaces other than that of symbol sequences, by using binary-encoded symbols, such as date expressions or numbers in decimal encoding. For instance, different syntactic forms of a date expression may represent the same date but consist of different strings.

Examples:

  “the quick brown fox jumps over the lazy dog”

  “6F 6E 54 79 70 31 0D 9E”

In first-order logic:

E62(x) E59(x)

E63 Beginning of Existence

Subclass of:

E5 Event

Superclass of:

E12 Production

E65 Creation

E66 Formation

E67 Birth

E81 Transformation

Scope note:

This class comprises events that bring into existence any instance of E77 Persistent Item.

It may be used for temporal reasoning about things (intellectual products, physical items, groups of people, living beings) beginning to exist; it serves as a hook for both a terminus post quem and a terminus ante quem.

Examples:

  the birth of my child (E67) (fictitious)

  the birth of Snoopy, my dog (fictitious)

  the calving of the iceberg that sank the Titanic

  the construction of the Eiffel Tower (E12) (Tissandier, 1889)

In first-order logic:

E63(x) E5(x)

Properties:

P92 brought into existence (was brought into existence by): E77 Persistent Item

E64 End of Existence

Subclass of:

E5 Event

Superclass of:

E6 Destruction

E68 Dissolution

E69 Death

E81 Transformation

Scope note:

This class comprises events that end the existence of any instance of E77 Persistent Item.

It may be used for temporal reasoning about things (physical items, groups of people, living beings) ceasing to exist; it serves as a hook both a terminus post quem and a terminus ante quem. In cases where substance from an instance of E77 Persistent Item continues to exist in a new form, the process would be documented as instances of E81 Transformation.

Examples:

  the death of Snoopy, my dog (fictitious)

  the melting of the snowman (E6)

  the burning of the Temple of Artemis in Ephesos by Herostratos in 356 BC (E7, E6) (Trell, 1945)

In first-order logic:

E64(x) E5(x)

Properties:

P93 took out of existence (was taken out of existence by): E77 Persistent Item

E65 Creation

Subclass of:

E7 Activity

E63 Beginning of Existence

Superclass of:

E83 Type Creation

Scope note:

This class comprises events that result in the creation of conceptual items or immaterial products, such as legends, poems, texts, music, images, movies, laws, types, etc.

Examples:

  the framing of the U.S. Constitution (Farrand, 1913)

  the drafting of U.N. Resolution 1441 (United Nations Security Council, 2002)

In first-order logic:

E65(x) E7(x)

E65(x) E63(x)

Properties:

P94 has created (was created by): E28 Conceptual Object

E66 Formation

Subclass of:

E7 Activity

E63 Beginning of Existence

Scope note:

This class comprises events that result in the formation of a formal or informal E74 Group of people, such as a club, society, association, corporation, or nation.

E66 Formation does not include the arbitrary aggregation of people who do not act as a collective.

The formation of an instance of E74 Group does not require that the group is populated with members at the time of formation. In order to express the joining of members at the time of formation, the respective activity should be simultaneously an instance of both E66 Formation and E85 Joining.

Examples:

  the formation of the CIDOC CRM Special Interest Group in 2000

  the formation of the Soviet Union (Pipes, 1964)

  the conspiring of the murderers of Caesar (Irwin, 1935)

In first-order logic:

E66(x) E7(x)

E66(x) E63(x)

Properties:

P95 has formed (was formed by): E74 Group

P151 was formed from (participated in): E74 Group

E67 Birth

Subclass of:

E63 Beginning of Existence

Scope note:

This class comprises the births of human beings. E67 Birth is a biological event focussing on the context of people coming into life. (E63 Beginning of Existence comprises the coming into life of any living being.)

Twins, triplets, etc. are brought into life by the same instance of E67 Birth. The introduction of the E67 Birth event as a documentation element allows the description of a range of family relationships in a simple model. Suitable extensions may describe more details and the complexity of motherhood since the advent of modern medicine. In this model, the biological father is not seen as a necessary participant in the E67 Birth.

Examples:

  the birth of Alexander the Great (Stoneman, 2004)

In first-order logic:

E67(x) E63(x)

Properties:

P96 by mother (gave birth): E21 Person

P97 from father (was father for): E21 Person

P98 brought into life (was born): E21 Person

E68 Dissolution

Subclass of:

E64 End of Existence

Scope note:

This class comprises the events that result in the formal or informal termination of an instance of E74 Group.

If the dissolution was deliberate, the Dissolution event should also be instantiated as an instance of E7 Activity.

Examples:

  the fall of the Roman Empire (Whittington, 1964)

  the liquidation of Enron Corporation (Atlas, 2001)

In first-order logic:

E68(x) E64(x)

Properties:

P99 dissolved (was dissolved by): E74 Group

E69 Death

Subclass of:

E64 End of Existence

Scope note:

This class comprises the deaths of human beings.

If a person is killed, their death should be instantiated as E69 Death and as E7 Activity. The death or perishing of other living beings should be documented as instances of E64 End of Existence.

Examples:

  the murder of Julius Caesar (E69, E7) (Irwin, 1935)

  the death of Senator Paul Wellstone (Monast and Tao, 2002)

In first-order logic:

E69(x) E64(x)

Properties:

P100 was death of (died in): E21 Person

E70 Thing

Subclass of:

E77 Persistent Item

Superclass of:

E71 Human-Made Thing

E72 Legal Object

Scope note:

This general class comprises discrete, identifiable, instances of E77 Persistent Item that are documented as single units, that either consist of matter or depend on being carried by matter and are characterized by relative stability.

They may be intellectual products or physical things. They may, for instance, have a solid physical form, an electronic encoding, or they may be a logical concept or structure.

Examples:

  my photograph collection (E78) (fictitious)

  the bottle of milk in my refrigerator (E22) (fictitious)

  the Riss A1 plan of the Straßburger Münster (French: Cathédrale Notre-Dame de Strasbourg) (E29) (Liess, R., 1985)

  the thing on the top of Otto Hahn’s desk (E19)

  the form of the no-smoking sign (E36)

  the cave of Dirou, Mani, Greece (E26) (Psimenos, 2005)

In first-order logic:

E70(x) E77(x)

Properties:

P43 has dimension (is dimension of): E54 Dimension

P101 had as general use (was use of): E55 Type

P130 shows features of (features are also found on): E70 Thing

(P130.1 kind of similarity: E55 Type)

E71 Human-Made Thing

Subclass of:

E70 Thing

Superclass of:

E24 Physical Human-Made Thing

E28 Conceptual Object

Scope note:

This class comprises discrete, identifiable human-made items that are documented as single units.

These items are either intellectual products or human-made physical things, and are characterized by relative stability. They may, for instance, have a solid physical form, an electronic encoding, or they may be logical concepts or structures.

Examples:

  Beethoven’s 5th Symphony (E73) (Lockwood, 2015)

  Michelangelo’s David (E22) (Paoletti and Bagemihl, 2015)

  Einstein’s Theory of General Relativity (E89) (Hartle, 2003)

  the taxon ‘Fringilla coelebs Linnaeus,1758’ (E55) (Sinkevicius and Narusevicius, 2002)

In first-order logic:

E71(x) E70(x)

Properties:

P102 has title (is title of): E35 Title

(P102.1 has type: E55 Type)

P103 was intended for (was intention of): E55 Type

E72 Legal Object

Subclass of:

E70 Thing

Superclass of:

E18 Physical Thing

E90 Symbolic Object

Scope note:

This class comprises those material or immaterial items to which instances of E30 Right, such as the right of ownership or use, can be applied.

This is generally true for all instances of E18 Physical Thing. In the case of instances of E28 Conceptual Object, however, the identity of an instance of E28 Conceptual Object or the method of its use may be too ambiguous to reliably establish instances of E30 Right, as in the case of taxa and inspirations. Ownership of corporations is currently regarded as out of scope of the CIDOC CRM.

Examples:

  the Cullinan diamond (E19) (Scarratt and Shor, 2006)

  definition of the CIDOC Conceptual Reference Model Version 5.0.4 (E73) (ISO 21127: 2014)

In first-order logic:

E72(x) E70(x)

Properties:

P104 is subject to (applies to): E30 Right

P105 right held by (has right on): E39 Actor

E73 Information Object

Subclass of:

E89 Propositional Object

E90 Symbolic Object

Superclass of:

E29 Design or Procedure

E31 Document

E33 Linguistic Object

E36 Visual Item

Scope note:

This class comprises identifiable immaterial items, such as poems, jokes, data sets, images, texts, multimedia objects, procedural prescriptions, computer program code, algorithm or mathematical formulae, that have an objectively recognizable structure and are documented as single units. The encoding structure known as a “named graph” also falls under this class, so that each “named graph” is an instance of E73 Information Object.

An instance of E73 Information Object does not depend on a specific physical carrier, which can include human memory, and it can exist on one or more carriers simultaneously.

Instances of E73 Information Object of a linguistic nature should be declared as instances of the E33 Linguistic Object subclass. Instances of E73 Information Object of a documentary nature should be declared as instances of the E31 Document subclass. Conceptual items such as types and classes are not instances of E73 Information Object, nor are ideas without a reproducible expression.

Examples:

  image BM000038850.JPG from the Clayton Herbarium in London (E31) (Natural History Museum, 2021)

  E. A. Poe's “The Raven” (Poe, 1869)

  the movie “The Seven Samurai” by Akira Kurosawa (Mellen, 2002)

  the text of Huray describing the Maxwell Equations (Huray, 2010)

  the Getty AAT as published as Linked Open Data, accessed 1/10/2014

In first-order logic:

E73(x) E89(x)

E73(x) E90(x)

Properties:

P165 incorporates (is incorporated in): E90 Symbolic Object

E74 Group

Subclass of:

E39 Actor

Scope note:

This class comprises any gatherings or organizations of human individuals or groups that act collectively or in a similar way due to any form of unifying relationship. In the wider sense this class also comprises official positions which used to be regarded in certain contexts as one actor, independent of the current holder of the office, such as the president of a country. In such cases, it may happen that the group never had more than one member. A joint pseudonym (i.e. a name that seems indicative of an individual but that is actually used as a persona by two or more people) is a particular case of E74 Group.

A gathering of people becomes an instance of E74 Group when it exhibits organizational characteristics usually typified by a set of ideas or beliefs held in common, or actions performed together. These might be communication, creating some common artifact, a common purpose such as study, worship, business, sports, etc. Nationality can be modelled as membership in an instance of E74 Group. Married couples and other concepts of family are regarded as particular examples of E74 Group.

Examples:

  the Impressionists (Wilson, 1994)

  the Navajo (Correll, 1972)

  the Greeks (Williams, 1993)

  the peace protestors in New York City on 15th February 2003

  Exxon-Mobil (Raymond, 2006)

  King Solomon and his wives (Thieberger, 1947)

  the President of the Swiss Confederation

  Nicolas Bourbaki [the collective pseudonym of a group of mathematicians, predominantly French alumni of the École normale supérieure] (Aczel, 2007)

  Betty Crocker (Crocker, 2012)

  Ellery Queen [Ellery Queen is a pseudonym created in 1929 by American crime fiction writers Frederic Dannay and Manfred Bennington Lee.] (Wheat, 2005)

  Greenpeace

  Paveprime Ltd

  the National Museum of Denmark

In first-order logic:

E74(x) E39(x)

Properties:

P107 has current or former member (is current or former member of): E39 Actor

(P107.1 kind of member: E55 Type)

E77 Persistent Item

Subclass of:

E1 CRM Entity

Superclass of:

E39 Actor

E70 Thing

Scope note:

This class comprises items that have persistent characteristics of structural nature substantially related to their identity and their integrity, sometimes known as “endurants” in philosophy. Persistent Items may be physical entities, such as people, animals or things, conceptual entities such as ideas, concepts, products of the imagination or even names.

Instances of E77 Persistent Item may be present or be part of interactions in different periods or events. They can repeatedly be recognized at disparate occasions during their existence by characteristics of structural nature. The respective characteristics need not be exactly the same during all the existence of an instance of E77 Persistent Item. Often, they undergo gradual change, still bearing some similarities with that of previous times, or disappear completely and new emerge. For instance, a person, from the time of being born on, will gradually change all its features and acquire new ones, such as a scar. Even the DNA in different body cells will develop defects and mutations. Nevertheless, relevant characteristics used should be sufficiently similar to recognize the instance for some substantial period of time.

The more specific criteria that determine the identity of instances of subclasses of E77 Persistent Item may vary considerably and are described or referred to in the respective scope notes. The decision about which exact criteria to use depends on whether the observable behaviour of the respective part of reality such confined conforms to the reasoning the user is interested in. For example, a building can be regarded as no longer existing if it is dismantled and the materials reused in a different configuration. On the other hand, human beings go through radical and profound changes during their life-span, affecting both material composition and form, yet preserve their identity by other criteria, such as being bodily separated from other persons. Similarly, inanimate objects may be subject to exchange of parts and matter. On the opposite, the identity of a (version of a) text of a scientific publication is given by the exact arrangement of its relevant symbols.

The main classes of objects that fall outside the scope of the E77 Persistent Item class are temporal objects such as periods, events and acts, and descriptive properties.

An instance of E77 Persistent Item does not require actual knowledge of the identifying features of the instance being currently known. There may be cases, where the actual identifying features of an instance of E77 Persistent Item are not decidable at a particular state of knowledge.

Examples:

  Leonardo da Vinci (E21) (Strano, 1953)

  Stonehenge (E24) (Pryor, 2016)

  the hole in the ozone layer (E4) (Hufford and Horwitz, 2005)

  the First Law of Thermodynamics (E89) (Craig and Gislason, 2002)

  the Bermuda Triangle (E53) (Dolan, 2005)

In first-order logic:

E77(x) E1(x)

E78 Curated Holding

Subclass of:

E24 Physical Human-Made Thing

Scope note:

This class comprises aggregations of instances of E18 Physical Thing that are assembled and maintained (“curated” and “preserved,” in museological terminology) by one or more instances of E39 Actor over time for a specific purpose and audience, and according to a particular collection development plan. Typical instances of curated holdings are museum collections, archives, library holdings and digital libraries. A digital library is regarded as an instance of E18 Physical Thing because it requires keeping physical carriers of the electronic content.

Items may be added or removed from an E78 Curated Holding in pursuit of this plan. This class should not be confused with the E39 Actor maintaining the E78 Curated Holding who is often referred to using the name of the E78 Curated Holding (e.g. “The Wallace Collection decided…”).

Collective objects in the general sense, like a tomb full of gifts, a folder with stamps, or a set of chessmen, should be documented as instances of E19 Physical Object, and not as instances of E78 Curated Holding. This is because they form wholes, either because they are physically bound together or because they are kept together for their functionality.

Examples:

  the John Clayton Herbarium (Blake, 1918), (Natural History Museum, 2021)

  the Wallace Collection (Ingamells, 1990)

  Mikael Heggelund Foslie’s coralline red algae Herbarium at the Museum of Natural History and Archaeology, Trondheim, Norway (Woelkerling et al., 2005)

   the Digital Collections of the Munich DigitiZation Center (MDZ) accessible via https://www.digitale-sammlungen.de/ at least in January 2018.

In first-order logic:

E78(x) E24(x)