ISO 21127:2014
(Main)Information and documentation - A reference ontology for the interchange of cultural heritage information
Information and documentation - A reference ontology for the interchange of cultural heritage information
ISO 21127:2014 establishes guidelines for the exchange of information between cultural heritage institutions. In simple terms, this can be defined as the information managed by museums, libraries, and archives. The intended scope of this ISO 21127:2014 is defined as the exchange and integration of heterogeneous scientific documentation relating to museum collections. This definition requires further elaboration.
Information et documentation — Une ontologie de référence pour l'échange d'informations du patrimoine culturel
L'ISO 21127:2014 fixe des lignes directrices pour l'échange d'informations entre institutions patrimoniales. En termes simples, on peut dire qu'il s'agit de l'information gérée par les musées, les bibliothèques et les archives. Le domaine d'application visé par l'ISO 21127:2014 porte sur l'échange et l'intégration de la documentation scientifique hétérogène relative aux collections muséales. Cette définition appelle un développement.
Informatika in dokumentacija - Referenčna ontologija za izmenjavo informacij o kulturni dediščini
Ta mednarodni standard podaja smernice za izmenjavo informacij med institucijami za kulturno dediščino. Te so lahko preprosto opredeljene kot informacije, s katerimi upravljajo muzeji, knjižnice in arhivi.
Podrobnejšo opredelitev se lahko oblikuje tako, da se opredeli namenski obseg, tj. široka in kar najbolj vključujoča opredelitev splošnih načel, ter praktični obseg, ki je opredeljen s sklicem na skupino določenih standardov in praks glede muzejske dokumentacije.
Namenski obseg tega mednarodnega standarda je opredeljen kot izmenjava in integracija
heterogene znanstvene dokumentacije, ki je povezana z muzejskimi zbirkami. To opredelitev je treba dodatno izpopolniti.
– Izraz »znanstvena dokumentacija« določa zahtevo, da morata biti globina in kakovost opisnih informacij, ki jih lahko ureja ta mednarodni standard, ustrezni za resno akademsko raziskavo. To ne pomeni, da so informacije, namenjene predstavitvi širši publiki, izključene, ampak da je namen tega mednarodnega standarda zagotavljati raven podrobnosti in natančnosti, ki jo pričakujejo in zahtevajo muzejski strokovnjaki in raziskovalci na tem področju.
– Izraz »muzejske zbirke« zajema vse vrste materialov, ki jih zbirajo in razstavljajo
muzeji in z njimi povezane ustanove, kot določa ICOM). To vključuje zbirke, najdišča in spomenike, ki spadajo na področja, kot so družbena zgodovina, etnografija, arheologija, umetnost in uporabna umetnost, naravoslovje ter zgodovina znanosti in tehnologije.
– Dokumentiranje zbirk vključuje podroben opis posameznih elementov znotraj zbirk, skupin elementov in celotnih zbirk. Ta mednarodni standard zajema
kontekstualne informacije (tj. zgodovinsko, geografsko in teoretsko ozadje, ki muzejskim zbirkam dajejo dobršen del njihove kulturne pomembnosti in vrednosti).
– Izmenjava ustreznih informacij s knjižnicami in arhivi ter uskladitev z njihovimi
modeli spadata na predvideno področje uporabe tega mednarodnega standarda.
– Informacije, ki se zahtevajo samo za administrativne zadeve kulturnih ustanov in njihovo upravljanje, kot so informacije o osebju, računovodski podatki in statistike obiskovalcev, ne spadajo na predvideno področje uporabe tega mednarodnega standarda.
Praktični obseg tega mednarodnega standarda predstavlja skupina referenčnih standardov o muzejski
dokumentaciji, ki se uporabljajo za usmerjanje in ocenjevanje njenega razvoja. Ta mednarodni standard zajema isto domeno diskurza kot skupina teh referenčnih dokumentov; posledično se lahko za vse podatke, ki so pravilno zapisani skladno s katerimkoli od teh referenčnih dokumentov, oblikuje oblika zapisa, ki je združljiva s trenutnim standardom in hkrati ne vodi do pomenske izgube v podatkih.
General Information
Relations
Frequently Asked Questions
ISO 21127:2014 is a standard published by the International Organization for Standardization (ISO). Its full title is "Information and documentation - A reference ontology for the interchange of cultural heritage information". This standard covers: ISO 21127:2014 establishes guidelines for the exchange of information between cultural heritage institutions. In simple terms, this can be defined as the information managed by museums, libraries, and archives. The intended scope of this ISO 21127:2014 is defined as the exchange and integration of heterogeneous scientific documentation relating to museum collections. This definition requires further elaboration.
ISO 21127:2014 establishes guidelines for the exchange of information between cultural heritage institutions. In simple terms, this can be defined as the information managed by museums, libraries, and archives. The intended scope of this ISO 21127:2014 is defined as the exchange and integration of heterogeneous scientific documentation relating to museum collections. This definition requires further elaboration.
ISO 21127:2014 is classified under the following ICS (International Classification for Standards) categories: 35.240.30 - IT applications in information, documentation and publishing. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO 21127:2014 has the following relationships with other standards: It is inter standard links to ISO 21127:2023, ISO 21127:2006. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
You can purchase ISO 21127:2014 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of ISO standards.
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2017
,QIRUPDWLNDLQGRNXPHQWDFLMD5HIHUHQþQDRQWRORJLMD]DL]PHQMDYRLQIRUPDFLMR
NXOWXUQLGHGLãþLQL
Information and documentation -- A reference ontology for the interchange of cultural
heritage information
Information et documentation -- Une ontologie de référence pour l'échange
d'informations du patrimoine culturel
Ta slovenski standard je istoveten z: ISO 21127:2014
ICS:
35.240.99 8SRUDEQLãNHUHãLWYH,7QD IT applications in other fields
GUXJLKSRGURþMLK
97.195 8PHWQLãNLLQREUWQLãNLL]GHONL Items of art and handicrafts.
.XOWXUQHGREULQHLQNXOWXUQD Cultural property and
GHGLãþLQD heritage
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL ISO
STANDARD 21127
Second edition
2014-10-15
Information and documentation — A
reference ontology for the interchange
of cultural heritage information
Information et documentation — Une ontologie de référence pour
l’échange d’informations du patrimoine culturel
Reference number
©
ISO 2014
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
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Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
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Published in Switzerland
ii © ISO 2014 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Conformance . 1
3 Terms and definitions . 2
4 Structure and presentation . 6
4.1 Property quantifiers . 6
4.2 Naming conventions . 8
5 Modelling principles . 9
5.1 Monotonicity . 9
5.2 Minimality . 9
5.3 Shortcuts . 9
5.4 Disjointness .10
5.5 Types.10
5.6 Extensions .11
5.7 Coverage of intended scope .11
6 Class declarations .12
7 Property declarations .54
Annex A (informative) Class hierarchy .98
Bibliography .104
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 46, Information and documentation, Subcommittee
SC 4, Technical interoperability, in collaboration with the International Council of Museums Committee
for Documentation (ICOM CIDOC).
This second edition cancels and replaces the first edition (ISO 21127:2006), which has been technically
revised.
iv © ISO 2014 – All rights reserved
Introduction
This International Standard is the culmination of more than a decade of standards development work
by the International Committee for Documentation (CIDOC) of the International Council of Museums
(ICOM). Work on this International Standard began in 1996 under the auspices of the ICOM-CIDOC
1)
Documentation Standards Working Group. The document provided by CIDOC formed the basis for
ISO 21127 which was first published in 2006. While the initial impetus for the work came from the
museum community, it has since spread to encompass other types of cultural heritage institution. This
International Standard has been appropriated and extended to meet the needs of other institutions
dealing with cultural heritage.
The primary purpose of this International Standard is to offer a conceptual basis for the mediation
of information between cultural heritage organizations such as museums, libraries, and archives.
This International Standard aims to provide a common reference point against which divergent and
incompatible sources of information can be compared and, ultimately, harmonized.
2)
[1]
ISO 21127 is an ontology for cultural heritage information: a formal representation of the conceptual
scheme, or “world view”, underlying the database applications and documentation systems that are used
by cultural heritage institutions. It is important to note that this International Standard aims to clarify
the logic of what cultural heritage institutions do in fact document; it is not intended as a normative
specification of what they should document. The primary role of this International Standard is to enable
information exchange and integration between heterogeneous sources of cultural heritage information.
It aims to provide the semantic definitions and clarifications needed to transform disparate, localized
information sources into a coherent global resource, be it within an institution, an intranet, or on the
Internet.
The specific aims of this International Standard are to
— serve as a common language for domain experts and IT developers when formulating requirements,
— 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. These transformation algorithms are
useful for data exchange, data migration from legacy systems, data information integration, and
mediation of heterogeneous sources,
— support associative queries against integrated resources by providing a global model of the basic
classes and their associations to formulate such queries, and
— provide developers of information systems with a guide to good practice in conceptual modelling.
The ISO 21127 ontology is expressed as a series of interrelated concepts with definitions. This
presentation is similar to that used for a thesaurus. However, the ontology is not intended as a terminology
standard and does not set out to define the terms that are typically used as data in cultural heritage
documentation. Although the presentation provided here is complete, it is an intentionally compact
and concise presentation of the ontology’s 86 classes and 137 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 137). However, this definition
does contain all the information needed to infer and automatically generate a full declaration of all
properties, including inherited properties.
1) The CIDOC CRM Special Interest Group continues to maintain a version of this original document, usually
known as the “CIDOC Conceptual Reference Model” or CIDOC CRM.
2) In the sense used in computer science, i.e. it describes in a formal language the relevant explicit and implicit
concepts and the relationships between them.
INTERNATIONAL STANDARD ISO 21127:2014(E)
Information and documentation — A reference ontology
for the interchange of cultural heritage information
1 Scope
This International Standard establishes guidelines for the exchange of information between cultural
heritage institutions. In simple terms, this can be defined as the information managed by museums,
libraries, and archives.
A more detailed definition can be articulated by defining both the intended scope, a broad and maximally
inclusive definition of general principles, and the practical scope, which is defined by reference to a set
of specific museum documentation standards and practices.
The intended scope of this International Standard is defined as the exchange and integration of
heterogeneous scientific documentation relating to museum collections. This definition requires further
elaboration.
— The term “scientific documentation” is intended to convey the requirement that the depth and quality
of descriptive information that can be handled by this International Standard need to 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 this International Standard is intended
to provide the level of detail and precision expected and required by museum professionals and
researchers in the field.
— The term “museum collections” is intended to cover all types of material collected and displayed
3)
by museums and related institutions, as defined by ICOM . This includes collections, sites, and
monuments relating to fields such as social history, ethnography, archaeology, fine and applied arts,
natural history, history of sciences and technology.
— The documentation of collections includes the detailed description of individual items within
collections, groups of items, and collections as a whole. This International Standard is specifically
intended to cover contextual information (i.e. the historical, geographical, and theoretical
background that gives museum collections much of their cultural significance and value).
— The exchange of relevant information with libraries and archives, and harmonization with their
models, falls within the intended scope of this International Standard.
— 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 this International Standard.
4)
The practical scope of this International Standard is the set of reference standards for museum
documentation that have been used to guide and validate its development. This International Standard
covers the same domain of discourse as the union of these reference documents; consequently, for any
data that is correctly encoded in accordance with any of these reference documents, a form of encoding
can be created that is both compatible with the current standard and which entails no semantic loss.
2 Conformance
Users intending to take advantage of the semantic interoperability offered by this International Standard
should ensure conformance with the relevant data structures. Conformance pertains either to data
3) The ICOM Statutes provide a definition of the term “museum” at .
4) The practical scope of the CIDOC CRM, including a list of the relevant museum documentation standards, is
discussed in more detail on the CIDOC CRM website at < http://cidoc-crm.org/scope.html >.
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 this International Standard 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 information, 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 this International Standard 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.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
class
category of items that share one or more common traits
Note 1 to entry: Class traits serve as criteria to identify items that belong to the class. These traits need not be
explicitly formulated in logical terms, but can be described in a text (called a scope note) that refers to a common
conceptualization of domain experts. The sum of these traits is called the intension of the class. A class can 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 can bring new instances into being 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 need to have an unambiguously defined domain and range). For example, “Person” is a class. A “Person” can
have the property of being a member of a “Group”, but this is not a necessary condition for being a “Person”. We
will never know all “Persons” who have lived in the past, and there will be more “Persons” in the future. Classes
are usually organized as a class hierarchy. The relationship between a subclass and its superclass is known as the
IsA relationship (a concatenation of the words “is a”). For example, a ship IsA vehicle.
3.2
complement
〈of a class A〉 set of all instances of its superclass, B, that are not instances of class A
Note 1 to entry: In terms of set theory, the complement of a class is the extension of the superclass minus the
extension of the class. Compatible extensions of this International Standard need not declare any class as the
complement of one or more other classes. To do so would violate the goal of describing an open world. For example,
for all possible cases of human gender, “male” need not be declared as the complement of “female” or vice versa.
3.3
disjoint
having no common instances in any possible world
Note 1 to entry: Classes are disjoint if the intersection of their extensions is necessarily an empty set.
2 © ISO 2014 – All rights reserved
Note 2 to entry: See also 5.4.
3.4
domain
class for which a property is formally defined
Note 1 to entry: Instances of a property are applicable to instances of its domain class. A property needs
to have exactly one domain, though the domain class can always contain instances for which the property is
not instantiated. The domain class is analogous to the grammatical subject of a phrase while the property is
analogous to the verb. Which class is selected as the domain and which as the range is arbitrary, as is the choice
between active or passive voice. Property names in ISO 21127 are designed to be semantically meaningful and
grammatically correct when read from domain to range. The inverse property name, given in parentheses, is also
designed to be semantically meaningful and grammatically correct when read from range to domain.
3.5
extension
set of all real life instances belonging to a class that fulfil the criteria of its intension
Note 1 to entry: The extension of a class is an “open” set in the sense that it is generally beyond our capabilities
to know all instances of a class in the world. The future can bring new instances into being at any time (open
world). An information system can, at any point in time, refer to some instances of a class, which form a subset of
its extension.
Note 2 to entry: See also 5.6.
3.6
inheritance
duplication of properties from a class to its subclasses
Note 1 to entry: Inheritance of properties from superclasses to subclasses entails that if an item x is an instance
of a class A, then all properties that need hold for the instances of any of the superclasses of A need also hold for
item x, and that all optional properties that can hold for the instances of any of the superclasses of A can also hold
for item x.
3.7
instance
item having properties that meet the criteria of the intension of the class
Note 1 to entry: “The Mona Lisa” is an instance of the class of E22 Man-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 Louvre is current owner of the Mona Lisa” is an
instance of the property “is current owner of”. One aspect of the open world assumption is that the number of
class instances declared in a given information system is usually less than the total number of instances in the
real world. You, for example, are an instance of “person”, but you are not mentioned in all information systems
describing “persons”.
3.8
intension
intended meaning of a class
Note 1 to entry: The intension of a class consists of one or more common traits shared by all instances of the class.
These need not be explicitly formulated in logical terms, but can simply be described in a text (a scope note) that
refers to a conceptualization shared by domain experts.
3.9
interoperability
capability of different information systems to communicate some of their contents
Note 1 to entry: Interoperability can imply that
a) two systems can exchange information, and/or
b) multiple systems can be accessed with a single method.
Note 2 to entry: Generally, syntactic interoperability is distinguished from semantic interoperability. Syntactic
interoperability means that the information encoding and the access protocols of the relevant systems are
compatible, so that information can be processed as described above without error. However, syntactic
interoperability alone does not ensure that each system processes the data in a manner consistent with the
intended meaning. For example, one system may contain a table called “actor” while another system uses the
name “agent”. Even if data from the two tables can be combined in a common data format, it will nonetheless
remain separated unless the semantic equivalence of the two tables is established. Semantic interoperability
requires more than compatible data formats. ISO 21127 presupposes existing syntactic interoperability and is
concerned only with adding semantic interoperability.
3.10
monotonic
〈of a knowledge base〉 having a set of conclusions derived through inference rules that does not reduce,
irrespective of whatever additional propositions can be inserted
Note 1 to entry: Monotonic reasoning is a term derived from knowledge representation. In practical terms,
as experts enter correct statements to an information system, the system need not regard any of the existing
statements as invalid. The ISO 21127 ontology is designed for monotonic reasoning and so enables conflict-free
merging of huge stores of knowledge.
Note 2 to entry: See also 5.1.
3.11
multiple inheritance
possibility for a class to have more than one immediate superclass
Note 1 to entry: 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,
then some classes will inevitably be repeated at different positions in the hierarchy. For example, “person” is both
an “actor” and a “biological object”.
3.12
open world
assumption that the information stored in a knowledge base is incomplete with respect to the universe
of discourse it aims to describe
Note 1 to entry: A term derived from knowledge representation. The incompleteness of a knowledge base can
be due to the inability of the maintainer to provide sufficient information, or to more fundamental problems of
cognition in the system’s domain. Such problems are characteristic of cultural information systems since our
records about the past are necessarily incomplete. In addition, some items cannot be clearly assigned to a given
class. In particular, the absence of a certain trait for an item described in the system does not necessarily entail
that the item does not possess the trait. For example, if one item is described as “biological object” and another
as “physical object”, this does not imply that the latter is not also a “biological object”. Therefore, complements of
a class with respect to a superclass cannot be derived in general from an information system based on the open
world assumption.
3.13
primitive concept
concept that is declared and for which the meaning is clear, but which cannot be derived from other
concepts
Note 1 to entry: Primitive concept is a term derived from knowledge representation. For example, mother can
be described as a female who has given birth to a child, so mother is not a primitive concept. Event however is a
primitive concept. ISO 21127 is composed primarily of primitive concepts.
4 © ISO 2014 – All rights reserved
3.14
property
named characteristic of a class to which values can be assigned
Note 1 to entry: A property is characterized by an intension, which is conveyed by a scope note. A property plays
a role analogous to a verb in that it needs to be defined with reference to both a domain and range, which are
analogous to the subject and object in a phrase (unlike classes, which can be defined independently). Which class
is selected as the domain and which as the range, is arbitrary, as is the choice between active and passive voice. In
other words, a property can be interpreted in both directions, with two distinct but related interpretations. For
example, “E24 Physical man-made thing depicts E1 Entity” is equivalent to “E1 Entity is depicted by E24 Physical
man-made thing”. Properties can 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.
3.15
query
request for information from an information system expressed so that the response can be calculated
automatically
3.16
query containment
query X contains another query Y if, for each possible population of a database, the answer set to query X
also contains the answer set to query Y
Note 1 to entry: If query X and Y were classes, then X would be a superclass of Y.
3.17
range
class that comprises all the potential values of a property
Note 1 to entry: The value of a property at a given time is an instance of the class assigned as the range of the
property. A property is intended to have exactly one range class. A rough analogy can be drawn between the
subject-verb-object structure of a basic proposition and the domain-property-range structure defined in the
standard. The range class corresponds to the grammatical object. Which class is selected as domain, and which as
range, is arbitrary, as is the choice between active and passive voice. Property names in ISO 21127 are designed
to be semantically meaningful and grammatically correct when read from domain to range. The inverse property
name, given in parentheses, is designed to be semantically meaningful and grammatically correct when read
from range to domain.
3.18
scope note
textual description of the intension of a class or property
Note 1 to entry: Scope notes are not formal modelling constructs but are provided to help explain the intended
meaning and application of the classes and properties. Basically, they refer to a conceptualization shared by domain
experts and disambiguate different possible interpretations. Illustrative examples of classes and properties are
also provided with the scope notes for explanatory purposes.
3.19
shortcut
formally defined single property that represents a deduction or join of a data path in the ontology
Note 1 to entry: The scope notes of shortcut properties provide a verbal description of the equivalent deduction.
Shortcuts are introduced for those 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 E16 measurement that observed it. The International Standard allows shortcuts as
cases of less detailed knowledge, while preserving in its schema the relationship to the full information.
Note 2 to entry: See also 5.3.
3.20
strict inheritance
properties inheritance that allows no exceptions
Note 1 to entry: Some systems can declare that “elephants are grey” and regard a white elephant as an exception.
Under strict inheritance rules it would hold that if all elephants were indeed grey, then a white elephant could not
be an elephant. Obviously not all elephants are grey; being grey is not part of the intension of the concept elephant
but an optional property. The International Standard applies strict inheritance as a normalization principle.
3.21
subclass
specialization of another class, i.e. the superclass
Note 1 to entry: A subclass inherits all the properties of its superclass (i.e. strict inheritance), in addition to having
none, one, or more additional properties of its own. A subclass can have more than one immediate superclass,
and consequently inherits the properties of all of its superclasses (i.e. multiple inheritance). A subclass has
an IsA relationship to its superclass(es): every instance of the subclass is also, by definition, an instance of the
superclass(es). For example, every “person” IsA “biological object”.
3.22
subproperty
specialization of another property, i.e. the superproperty
Note 1 to entry: All instances of a subproperty are also instances of its superproperty. The intension of a subproperty
extends the intension of its superproperty, i.e. its traits are more restrictive than that of its superproperty. The
domain of a subproperty is a subclass of the domain of its superproperty. The range of a subproperty is a subclass
of the range of its superproperty. Instances of a subproperty inherit 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 their own.
Note 2 to entry: 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 we call a property hierarchy. The IsA relationship is transitive and
shall not be cyclic. In some object-oriented languages, including C++, there is no equivalent to the specialization
of properties.
3.23
superclass
generalization of one or more other classes, i.e. the subclasses
Note 1 to entry: A superclass subsumes all instances of its subclasses, and 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.
The subsumption relationship or generalization is the inverse of the IsA relationship or specialization. In some
contexts (e.g. the programming language C++) the term parent class is used synonymously with superclass. For
example, “biological object subsumes person” is synonymous with “biological object is a superclass of person”.
Fewer properties are needed to identify an item as a “biological object” than to identify it as a “person”.
3.24
superproperty
generalization of one or more other properties, i.e. the subproperties
Note 1 to entry: A superproperty subsumes all instances of its subproperties, and 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.
4 Structure and presentation
4.1 Property quantifiers
Quantifiers for properties are provided for the purpose of semantic clarification only, and should
not be treated as implementation recommendations. This International Standard has been designed
6 © ISO 2014 – All rights reserved
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.
Table 1 lists all possible property quantifiers occurring in this International Standard according to their
notation, together with a textual explanation. In order to provide optimal clarity, two widely accepted
notations are used in this International Standard, i.e. one verbal, the other numerical. The verbal
notation uses phrases such as “one to many”, and the numerical notation expressions such as “(0,n:0,1)”.
The terms “one”, “many”, and “necessary” are fairly intuitive; the term “dependent” is less obvious. It
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.
Table 1 — Property quantifiers
Quantifier Description
many to many 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
(0,n:0,n)
optional and repeatable for its domain and range.
one to many 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
(0,n:0,1)
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 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
(0,1:0,n)
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, nec- An individual domain instance of this property can have one or more instances of the
essary 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
(1,n:0,n)
optional and repeatable for its range.
one to many, neces- An individual domain instance of this property can have one or more instances of the
sary 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
(1,n:0,1)
domain, and optional but not repeatable for its range. This situation is sometimes called
a “fan-out”.
many to one, neces- An individual domain instance of this property shall have exactly one instance of the
sary 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
(1,1:0,n)
for its domain, and optional and repeatable for its range. This situation is sometimes
called a “fan-in”.
one to many, An individual domain instance of this property can have zero, one, or more instances
dependent of the property, but an individual range instance shall be referenced by exactly one
instance of the property. In other words, this property is optional and repeatable for
(0,n:1,1)
its domain, but necessary and not repeatable for its range. This situation is sometimes
called a “fan-out”.
one to many, neces- An individual domain instance of this property can have one or more instances of the
sary, dependent property, but an individual range instance shall be referenced by exactly one instance
of the property. In other words, the property is necessary and repeatable for its domain,
(1,n:1,1)
and necessary but not repeatable for its range. This situation is sometimes called a “fan-
out”.
many to one, neces- An individual domain instance of this property shall have exactly one instance of the
sary, dependent property, but an individual range instance can be referenced by one or more instances
of the property. In other words, this property is necessary and not repeatable for its
(1,1:1,n)
domain, and necessary and repeatable for its range. This situation is sometimes called a
“fan-in”.
Table 1 (continued)
Quantifier Description
one to one An individual domain instance and range instance of this property shall have exactly one
instance of the property. In other words, the property is necessary and not repeatable for
(1,1:1,1)
its domain and for its range.
NOTE Some properties are defined as being necessary for their domain or as being dependent for their
range. If such properties are not specified for an instance of the respective domain or range, it means that the
property exists, but that the value on one side of the property is unknown. In the case of optional properties,
no distinction is made between a value being unknown or the property not being applicable at all. For example,
one can know that an object has an owner, but not know who the owner is, or know that an object has no owner.
The model makes no distinction between these two cases. A textual note can be used for clarification if needed.
4.2 Naming conventions
The following naming conventions have been applied hereafter.
5)
— 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.
— Properties with a range that is a subclass of E59 Primitive Value (such as Ε1 Entity.P3 has note: E62
String) have no parenthetical name form as 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:
a) temporal entity and its subclasses;
b) thing and its subclasses;
c) actor and its subclasses;
d) other.
5) Some gaps are present in the numbering sequence used for classes and properties. This is intentional:
numbers assigned in previous versions of the standard to deprecated classes and properties have not been re-used.
8 © ISO 2014 – All rights reserved
5 Modelling principles
5.1 Monotonicity
Because this International Standard’s primary role is the meaningful integration of information in an
open world, it aims to be monotonic in the sense of domain theory. Existing constructs, and deductions
made from them, shall always remain valid and well-formed, i.e. even if new constructs and extensions
are added.
For example, one can add a subclass of E7 Activity to describe the use of a certain name for a place over
a certain time span by a particular group. By this extension, no existing IsA relationships or property
inheritances are compromised.
In addition, this International Standard aims to enable the formal preservation of monotonicity when
augmenting a compatible system. Existing instances, their properties, and deductions made from them,
should always remain valid and well-formed even as new instances are added to the system.
For example, if someone describes correctly that an item is an instance of E19 Physical Object and,
subsequently, 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.
I
...
INTERNATIONAL ISO
STANDARD 21127
Second edition
2014-10-15
Information and documentation — A
reference ontology for the interchange
of cultural heritage information
Information et documentation — Une ontologie de référence pour
l’échange d’informations du patrimoine culturel
Reference number
©
ISO 2014
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Conformance . 1
3 Terms and definitions . 2
4 Structure and presentation . 6
4.1 Property quantifiers . 6
4.2 Naming conventions . 8
5 Modelling principles . 9
5.1 Monotonicity . 9
5.2 Minimality . 9
5.3 Shortcuts . 9
5.4 Disjointness .10
5.5 Types.10
5.6 Extensions .11
5.7 Coverage of intended scope .11
6 Class declarations .12
7 Property declarations .54
Annex A (informative) Class hierarchy .98
Bibliography .104
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 46, Information and documentation, Subcommittee
SC 4, Technical interoperability, in collaboration with the International Council of Museums Committee
for Documentation (ICOM CIDOC).
This second edition cancels and replaces the first edition (ISO 21127:2006), which has been technically
revised.
iv © ISO 2014 – All rights reserved
Introduction
This International Standard is the culmination of more than a decade of standards development work
by the International Committee for Documentation (CIDOC) of the International Council of Museums
(ICOM). Work on this International Standard began in 1996 under the auspices of the ICOM-CIDOC
1)
Documentation Standards Working Group. The document provided by CIDOC formed the basis for
ISO 21127 which was first published in 2006. While the initial impetus for the work came from the
museum community, it has since spread to encompass other types of cultural heritage institution. This
International Standard has been appropriated and extended to meet the needs of other institutions
dealing with cultural heritage.
The primary purpose of this International Standard is to offer a conceptual basis for the mediation
of information between cultural heritage organizations such as museums, libraries, and archives.
This International Standard aims to provide a common reference point against which divergent and
incompatible sources of information can be compared and, ultimately, harmonized.
2)
[1]
ISO 21127 is an ontology for cultural heritage information: a formal representation of the conceptual
scheme, or “world view”, underlying the database applications and documentation systems that are used
by cultural heritage institutions. It is important to note that this International Standard aims to clarify
the logic of what cultural heritage institutions do in fact document; it is not intended as a normative
specification of what they should document. The primary role of this International Standard is to enable
information exchange and integration between heterogeneous sources of cultural heritage information.
It aims to provide the semantic definitions and clarifications needed to transform disparate, localized
information sources into a coherent global resource, be it within an institution, an intranet, or on the
Internet.
The specific aims of this International Standard are to
— serve as a common language for domain experts and IT developers when formulating requirements,
— 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. These transformation algorithms are
useful for data exchange, data migration from legacy systems, data information integration, and
mediation of heterogeneous sources,
— support associative queries against integrated resources by providing a global model of the basic
classes and their associations to formulate such queries, and
— provide developers of information systems with a guide to good practice in conceptual modelling.
The ISO 21127 ontology is expressed as a series of interrelated concepts with definitions. This
presentation is similar to that used for a thesaurus. However, the ontology is not intended as a terminology
standard and does not set out to define the terms that are typically used as data in cultural heritage
documentation. Although the presentation provided here is complete, it is an intentionally compact
and concise presentation of the ontology’s 86 classes and 137 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 137). However, this definition
does contain all the information needed to infer and automatically generate a full declaration of all
properties, including inherited properties.
1) The CIDOC CRM Special Interest Group continues to maintain a version of this original document, usually
known as the “CIDOC Conceptual Reference Model” or CIDOC CRM.
2) In the sense used in computer science, i.e. it describes in a formal language the relevant explicit and implicit
concepts and the relationships between them.
INTERNATIONAL STANDARD ISO 21127:2014(E)
Information and documentation — A reference ontology
for the interchange of cultural heritage information
1 Scope
This International Standard establishes guidelines for the exchange of information between cultural
heritage institutions. In simple terms, this can be defined as the information managed by museums,
libraries, and archives.
A more detailed definition can be articulated by defining both the intended scope, a broad and maximally
inclusive definition of general principles, and the practical scope, which is defined by reference to a set
of specific museum documentation standards and practices.
The intended scope of this International Standard is defined as the exchange and integration of
heterogeneous scientific documentation relating to museum collections. This definition requires further
elaboration.
— The term “scientific documentation” is intended to convey the requirement that the depth and quality
of descriptive information that can be handled by this International Standard need to 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 this International Standard is intended
to provide the level of detail and precision expected and required by museum professionals and
researchers in the field.
— The term “museum collections” is intended to cover all types of material collected and displayed
3)
by museums and related institutions, as defined by ICOM . This includes collections, sites, and
monuments relating to fields such as social history, ethnography, archaeology, fine and applied arts,
natural history, history of sciences and technology.
— The documentation of collections includes the detailed description of individual items within
collections, groups of items, and collections as a whole. This International Standard is specifically
intended to cover contextual information (i.e. the historical, geographical, and theoretical
background that gives museum collections much of their cultural significance and value).
— The exchange of relevant information with libraries and archives, and harmonization with their
models, falls within the intended scope of this International Standard.
— 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 this International Standard.
4)
The practical scope of this International Standard is the set of reference standards for museum
documentation that have been used to guide and validate its development. This International Standard
covers the same domain of discourse as the union of these reference documents; consequently, for any
data that is correctly encoded in accordance with any of these reference documents, a form of encoding
can be created that is both compatible with the current standard and which entails no semantic loss.
2 Conformance
Users intending to take advantage of the semantic interoperability offered by this International Standard
should ensure conformance with the relevant data structures. Conformance pertains either to data
3) The ICOM Statutes provide a definition of the term “museum” at .
4) The practical scope of the CIDOC CRM, including a list of the relevant museum documentation standards, is
discussed in more detail on the CIDOC CRM website at < http://cidoc-crm.org/scope.html >.
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 this International Standard 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 information, 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 this International Standard 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.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
class
category of items that share one or more common traits
Note 1 to entry: Class traits serve as criteria to identify items that belong to the class. These traits need not be
explicitly formulated in logical terms, but can be described in a text (called a scope note) that refers to a common
conceptualization of domain experts. The sum of these traits is called the intension of the class. A class can 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 can bring new instances into being 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 need to have an unambiguously defined domain and range). For example, “Person” is a class. A “Person” can
have the property of being a member of a “Group”, but this is not a necessary condition for being a “Person”. We
will never know all “Persons” who have lived in the past, and there will be more “Persons” in the future. Classes
are usually organized as a class hierarchy. The relationship between a subclass and its superclass is known as the
IsA relationship (a concatenation of the words “is a”). For example, a ship IsA vehicle.
3.2
complement
〈of a class A〉 set of all instances of its superclass, B, that are not instances of class A
Note 1 to entry: In terms of set theory, the complement of a class is the extension of the superclass minus the
extension of the class. Compatible extensions of this International Standard need not declare any class as the
complement of one or more other classes. To do so would violate the goal of describing an open world. For example,
for all possible cases of human gender, “male” need not be declared as the complement of “female” or vice versa.
3.3
disjoint
having no common instances in any possible world
Note 1 to entry: Classes are disjoint if the intersection of their extensions is necessarily an empty set.
2 © ISO 2014 – All rights reserved
Note 2 to entry: See also 5.4.
3.4
domain
class for which a property is formally defined
Note 1 to entry: Instances of a property are applicable to instances of its domain class. A property needs
to have exactly one domain, though the domain class can always contain instances for which the property is
not instantiated. The domain class is analogous to the grammatical subject of a phrase while the property is
analogous to the verb. Which class is selected as the domain and which as the range is arbitrary, as is the choice
between active or passive voice. Property names in ISO 21127 are designed to be semantically meaningful and
grammatically correct when read from domain to range. The inverse property name, given in parentheses, is also
designed to be semantically meaningful and grammatically correct when read from range to domain.
3.5
extension
set of all real life instances belonging to a class that fulfil the criteria of its intension
Note 1 to entry: The extension of a class is an “open” set in the sense that it is generally beyond our capabilities
to know all instances of a class in the world. The future can bring new instances into being at any time (open
world). An information system can, at any point in time, refer to some instances of a class, which form a subset of
its extension.
Note 2 to entry: See also 5.6.
3.6
inheritance
duplication of properties from a class to its subclasses
Note 1 to entry: Inheritance of properties from superclasses to subclasses entails that if an item x is an instance
of a class A, then all properties that need hold for the instances of any of the superclasses of A need also hold for
item x, and that all optional properties that can hold for the instances of any of the superclasses of A can also hold
for item x.
3.7
instance
item having properties that meet the criteria of the intension of the class
Note 1 to entry: “The Mona Lisa” is an instance of the class of E22 Man-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 Louvre is current owner of the Mona Lisa” is an
instance of the property “is current owner of”. One aspect of the open world assumption is that the number of
class instances declared in a given information system is usually less than the total number of instances in the
real world. You, for example, are an instance of “person”, but you are not mentioned in all information systems
describing “persons”.
3.8
intension
intended meaning of a class
Note 1 to entry: The intension of a class consists of one or more common traits shared by all instances of the class.
These need not be explicitly formulated in logical terms, but can simply be described in a text (a scope note) that
refers to a conceptualization shared by domain experts.
3.9
interoperability
capability of different information systems to communicate some of their contents
Note 1 to entry: Interoperability can imply that
a) two systems can exchange information, and/or
b) multiple systems can be accessed with a single method.
Note 2 to entry: Generally, syntactic interoperability is distinguished from semantic interoperability. Syntactic
interoperability means that the information encoding and the access protocols of the relevant systems are
compatible, so that information can be processed as described above without error. However, syntactic
interoperability alone does not ensure that each system processes the data in a manner consistent with the
intended meaning. For example, one system may contain a table called “actor” while another system uses the
name “agent”. Even if data from the two tables can be combined in a common data format, it will nonetheless
remain separated unless the semantic equivalence of the two tables is established. Semantic interoperability
requires more than compatible data formats. ISO 21127 presupposes existing syntactic interoperability and is
concerned only with adding semantic interoperability.
3.10
monotonic
〈of a knowledge base〉 having a set of conclusions derived through inference rules that does not reduce,
irrespective of whatever additional propositions can be inserted
Note 1 to entry: Monotonic reasoning is a term derived from knowledge representation. In practical terms,
as experts enter correct statements to an information system, the system need not regard any of the existing
statements as invalid. The ISO 21127 ontology is designed for monotonic reasoning and so enables conflict-free
merging of huge stores of knowledge.
Note 2 to entry: See also 5.1.
3.11
multiple inheritance
possibility for a class to have more than one immediate superclass
Note 1 to entry: 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,
then some classes will inevitably be repeated at different positions in the hierarchy. For example, “person” is both
an “actor” and a “biological object”.
3.12
open world
assumption that the information stored in a knowledge base is incomplete with respect to the universe
of discourse it aims to describe
Note 1 to entry: A term derived from knowledge representation. The incompleteness of a knowledge base can
be due to the inability of the maintainer to provide sufficient information, or to more fundamental problems of
cognition in the system’s domain. Such problems are characteristic of cultural information systems since our
records about the past are necessarily incomplete. In addition, some items cannot be clearly assigned to a given
class. In particular, the absence of a certain trait for an item described in the system does not necessarily entail
that the item does not possess the trait. For example, if one item is described as “biological object” and another
as “physical object”, this does not imply that the latter is not also a “biological object”. Therefore, complements of
a class with respect to a superclass cannot be derived in general from an information system based on the open
world assumption.
3.13
primitive concept
concept that is declared and for which the meaning is clear, but which cannot be derived from other
concepts
Note 1 to entry: Primitive concept is a term derived from knowledge representation. For example, mother can
be described as a female who has given birth to a child, so mother is not a primitive concept. Event however is a
primitive concept. ISO 21127 is composed primarily of primitive concepts.
4 © ISO 2014 – All rights reserved
3.14
property
named characteristic of a class to which values can be assigned
Note 1 to entry: A property is characterized by an intension, which is conveyed by a scope note. A property plays
a role analogous to a verb in that it needs to be defined with reference to both a domain and range, which are
analogous to the subject and object in a phrase (unlike classes, which can be defined independently). Which class
is selected as the domain and which as the range, is arbitrary, as is the choice between active and passive voice. In
other words, a property can be interpreted in both directions, with two distinct but related interpretations. For
example, “E24 Physical man-made thing depicts E1 Entity” is equivalent to “E1 Entity is depicted by E24 Physical
man-made thing”. Properties can 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.
3.15
query
request for information from an information system expressed so that the response can be calculated
automatically
3.16
query containment
query X contains another query Y if, for each possible population of a database, the answer set to query X
also contains the answer set to query Y
Note 1 to entry: If query X and Y were classes, then X would be a superclass of Y.
3.17
range
class that comprises all the potential values of a property
Note 1 to entry: The value of a property at a given time is an instance of the class assigned as the range of the
property. A property is intended to have exactly one range class. A rough analogy can be drawn between the
subject-verb-object structure of a basic proposition and the domain-property-range structure defined in the
standard. The range class corresponds to the grammatical object. Which class is selected as domain, and which as
range, is arbitrary, as is the choice between active and passive voice. Property names in ISO 21127 are designed
to be semantically meaningful and grammatically correct when read from domain to range. The inverse property
name, given in parentheses, is designed to be semantically meaningful and grammatically correct when read
from range to domain.
3.18
scope note
textual description of the intension of a class or property
Note 1 to entry: Scope notes are not formal modelling constructs but are provided to help explain the intended
meaning and application of the classes and properties. Basically, they refer to a conceptualization shared by domain
experts and disambiguate different possible interpretations. Illustrative examples of classes and properties are
also provided with the scope notes for explanatory purposes.
3.19
shortcut
formally defined single property that represents a deduction or join of a data path in the ontology
Note 1 to entry: The scope notes of shortcut properties provide a verbal description of the equivalent deduction.
Shortcuts are introduced for those 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 E16 measurement that observed it. The International Standard allows shortcuts as
cases of less detailed knowledge, while preserving in its schema the relationship to the full information.
Note 2 to entry: See also 5.3.
3.20
strict inheritance
properties inheritance that allows no exceptions
Note 1 to entry: Some systems can declare that “elephants are grey” and regard a white elephant as an exception.
Under strict inheritance rules it would hold that if all elephants were indeed grey, then a white elephant could not
be an elephant. Obviously not all elephants are grey; being grey is not part of the intension of the concept elephant
but an optional property. The International Standard applies strict inheritance as a normalization principle.
3.21
subclass
specialization of another class, i.e. the superclass
Note 1 to entry: A subclass inherits all the properties of its superclass (i.e. strict inheritance), in addition to having
none, one, or more additional properties of its own. A subclass can have more than one immediate superclass,
and consequently inherits the properties of all of its superclasses (i.e. multiple inheritance). A subclass has
an IsA relationship to its superclass(es): every instance of the subclass is also, by definition, an instance of the
superclass(es). For example, every “person” IsA “biological object”.
3.22
subproperty
specialization of another property, i.e. the superproperty
Note 1 to entry: All instances of a subproperty are also instances of its superproperty. The intension of a subproperty
extends the intension of its superproperty, i.e. its traits are more restrictive than that of its superproperty. The
domain of a subproperty is a subclass of the domain of its superproperty. The range of a subproperty is a subclass
of the range of its superproperty. Instances of a subproperty inherit 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 their own.
Note 2 to entry: 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 we call a property hierarchy. The IsA relationship is transitive and
shall not be cyclic. In some object-oriented languages, including C++, there is no equivalent to the specialization
of properties.
3.23
superclass
generalization of one or more other classes, i.e. the subclasses
Note 1 to entry: A superclass subsumes all instances of its subclasses, and 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.
The subsumption relationship or generalization is the inverse of the IsA relationship or specialization. In some
contexts (e.g. the programming language C++) the term parent class is used synonymously with superclass. For
example, “biological object subsumes person” is synonymous with “biological object is a superclass of person”.
Fewer properties are needed to identify an item as a “biological object” than to identify it as a “person”.
3.24
superproperty
generalization of one or more other properties, i.e. the subproperties
Note 1 to entry: A superproperty subsumes all instances of its subproperties, and 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.
4 Structure and presentation
4.1 Property quantifiers
Quantifiers for properties are provided for the purpose of semantic clarification only, and should
not be treated as implementation recommendations. This International Standard has been designed
6 © ISO 2014 – All rights reserved
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.
Table 1 lists all possible property quantifiers occurring in this International Standard according to their
notation, together with a textual explanation. In order to provide optimal clarity, two widely accepted
notations are used in this International Standard, i.e. one verbal, the other numerical. The verbal
notation uses phrases such as “one to many”, and the numerical notation expressions such as “(0,n:0,1)”.
The terms “one”, “many”, and “necessary” are fairly intuitive; the term “dependent” is less obvious. It
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.
Table 1 — Property quantifiers
Quantifier Description
many to many 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
(0,n:0,n)
optional and repeatable for its domain and range.
one to many 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
(0,n:0,1)
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 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
(0,1:0,n)
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, nec- An individual domain instance of this property can have one or more instances of the
essary 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
(1,n:0,n)
optional and repeatable for its range.
one to many, neces- An individual domain instance of this property can have one or more instances of the
sary 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
(1,n:0,1)
domain, and optional but not repeatable for its range. This situation is sometimes called
a “fan-out”.
many to one, neces- An individual domain instance of this property shall have exactly one instance of the
sary 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
(1,1:0,n)
for its domain, and optional and repeatable for its range. This situation is sometimes
called a “fan-in”.
one to many, An individual domain instance of this property can have zero, one, or more instances
dependent of the property, but an individual range instance shall be referenced by exactly one
instance of the property. In other words, this property is optional and repeatable for
(0,n:1,1)
its domain, but necessary and not repeatable for its range. This situation is sometimes
called a “fan-out”.
one to many, neces- An individual domain instance of this property can have one or more instances of the
sary, dependent property, but an individual range instance shall be referenced by exactly one instance
of the property. In other words, the property is necessary and repeatable for its domain,
(1,n:1,1)
and necessary but not repeatable for its range. This situation is sometimes called a “fan-
out”.
many to one, neces- An individual domain instance of this property shall have exactly one instance of the
sary, dependent property, but an individual range instance can be referenced by one or more instances
of the property. In other words, this property is necessary and not repeatable for its
(1,1:1,n)
domain, and necessary and repeatable for its range. This situation is sometimes called a
“fan-in”.
Table 1 (continued)
Quantifier Description
one to one An individual domain instance and range instance of this property shall have exactly one
instance of the property. In other words, the property is necessary and not repeatable for
(1,1:1,1)
its domain and for its range.
NOTE Some properties are defined as being necessary for their domain or as being dependent for their
range. If such properties are not specified for an instance of the respective domain or range, it means that the
property exists, but that the value on one side of the property is unknown. In the case of optional properties,
no distinction is made between a value being unknown or the property not being applicable at all. For example,
one can know that an object has an owner, but not know who the owner is, or know that an object has no owner.
The model makes no distinction between these two cases. A textual note can be used for clarification if needed.
4.2 Naming conventions
The following naming conventions have been applied hereafter.
5)
— 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.
— Properties with a range that is a subclass of E59 Primitive Value (such as Ε1 Entity.P3 has note: E62
String) have no parenthetical name form as 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:
a) temporal entity and its subclasses;
b) thing and its subclasses;
c) actor and its subclasses;
d) other.
5) Some gaps are present in the numbering sequence used for classes and properties. This is intentional:
numbers assigned in previous versions of the standard to deprecated classes and properties have not been re-used.
8 © ISO 2014 – All rights reserved
5 Modelling principles
5.1 Monotonicity
Because this International Standard’s primary role is the meaningful integration of information in an
open world, it aims to be monotonic in the sense of domain theory. Existing constructs, and deductions
made from them, shall always remain valid and well-formed, i.e. even if new constructs and extensions
are added.
For example, one can add a subclass of E7 Activity to describe the use of a certain name for a place over
a certain time span by a particular group. By this extension, no existing IsA relationships or property
inheritances are compromised.
In addition, this International Standard aims to enable the formal preservation of monotonicity when
augmenting a compatible system. Existing instances, their properties, and deductions made from them,
should always remain valid and well-formed even as new instances are added to the system.
For example, if someone describes correctly that an item is an instance of E19 Physical Object and,
subsequently, 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.
In order to formally preserve monotonicity in cases where opinions diverge, all formally defined
properties should be implemented with unconstrained cardinality (many:many) so that conflicting
instances of properties are merely accumulated. Knowledge stored in a conformant system can thus
serve as a research base, accumulating relevant alternative opinions around well-defined entities.
Conclusions about the truth or falsehood of the instances stored remain the subject of open-ended
scientific or scholarly hypothesis building.
For example, “El Greco” and even “King Arthur” should be treated as instances of E21 Person and be dealt
with as existing within the domain of discourse once they are entered into a knowledge base. Alternative
opinions about properties, such as their birthplace and the details of their lives, can be accumulated
without decisions concerning their veracity being required during data compilation.
5.2 Minimality
Although the scope of this International Standard is very broad, the ontology itself is constructed as
economically as possible.
— A class is not declared unless it is required as the domain or range of a property not appropriate to
its superclass, or it is a key concept in the practical scope.
— Classes and properties that share a superclass are non-exclusive by
...
NORME ISO
INTERNATIONALE 21127
Deuxième édition
2014-10-15
Information et documentation — Une
ontologie de référence pour l’échange
d’informations du patrimoine culturel
Information and documentation — A reference ontology for the
interchange of cultural heritage information
Numéro de référence
©
ISO 2014
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2014
Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni utilisée
sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie, l’affichage sur
l’internet ou sur un Intranet, sans autorisation écrite préalable. Les demandes d’autorisation peuvent être adressées à l’ISO à
l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Publié en Suisse
ii © ISO 2014 – Tous droits réservés
Sommaire Page
Avant-propos .iv
Introduction .v
1 Domaine d’application . 1
2 Conformité . 2
3 Termes et définitions . 2
4 Structure et présentation . 7
4.1 Quantificateurs des propriétés . 7
4.2 Conventions de nommage . 9
5 Principes de modélisation .10
5.1 Monotonicité .10
5.2 Minimalité .10
5.3 Raccourcis .10
5.4 Classes disjointes .11
5.5 Types.11
5.6 Extensions .13
5.7 Couverture du domaine d’application envisagé .13
6 Déclaration des classes .13
7 Déclaration des propriétés .61
Annexe A (informative) Hiérarchie des classes .108
Bibliographie .114
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes
nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est
en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.
L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui concerne
la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents
critères d’approbation requis pour les différents types de documents ISO. Le présent document a été
rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www.
iso.org/directives).
L’attention est appelée sur le fait que certains des éléments du présent document peuvent faire l’objet de
droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant les
références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de l’élaboration
du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de brevets reçues par
l’ISO (voir www.iso.org/brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la signification des termes et expressions spécifiques de l’ISO liés à l’évaluation de
la conformité, ou pour toute information au sujet de l’adhésion de l’ISO aux principes de l’OMC concernant
les obstacles techniques au commerce (OTC), voir le lien suivant: Avant-propos — Informations
supplémentaires.
Le comité chargé de l’élaboration du présent document est l’ISO/TC 46, Information et documentation,
sous-comité SC 4, Interopérabilité technique, en collaboration avec le Comité pour la Documentation du
Conseil International des Musées (ICOM-CIDOC).
Cette deuxième édition annule et remplace la première édition (ISO 21127:2006), qui a fait l’objet d’une
révision technique.
iv © ISO 2014 – Tous droits réservés
Introduction
La présente Norme internationale est l’aboutissement de plus d’une décennie de travail de la part du
Comité international pour la Documentation (CIDOC) du Conseil international des musées (ICOM). Le
travail sur la présente Norme internationale a commencé en 1996 sous les auspices du groupe de travail
1)
de l’ICOM-CIDOC sur la normalisation documentaire. Le document fourni par le CIDOC a servi de base
à la norme ISO 21127 publiée pour la première fois en 2006. Si ce travail a reçu son impulsion première
de la communauté muséale, il s’est depuis lors étendu à d’autres types d’institutions patrimoniales.
La présente Norme internationale a été adaptée et augmentée afin de répondre aux besoins d’autres
institutions s’occupant de patrimoine culturel.
L’objectif fondamental de la présente Norme internationale est d’offrir une base conceptuelle
pour l’interopérabilité des informations entre institutions patrimoniales telles que les musées, les
bibliothèques et les archives. L’intention est de fournir un point de référence commun avec lequel
des sources d’informations divergentes et incompatibles peuvent être comparées et, finalement,
harmonisées.
2)
[1]
L’ISO 21127 est une ontologie pour les informations concernant le patrimoine culturel: c’est une
représentation formelle du schéma conceptuel, ou «conception du monde», qui est sous-jacent aux
applications de base de données et aux systèmes de documentation qui sont employés par les institutions
patrimoniales. Il est important de noter que la présente Norme internationale vise à clarifier la logique
de ce que ces institutions documentent en pratique, et non pas à fournir des spécifications normatives
de ce qu’il convient qu’elles documentent. L’objectif fondamental de la présente Norme internationale
est de permettre l’échange et l’intégration d’informations entre sources hétérogènes sur le patrimoine
culturel. Elle vise à fournir les définitions et clarifications sémantiques requises pour transformer des
sources d’informations disparates et locales en une ressource universelle cohérente, que ce soit dans le
contexte d’une institution, d’un intranet ou de l’Internet
Les objectifs spécifiques de la présente Norme internationale sont de:
— servir de langage commun entre experts du domaine et informaticiens, lors de l’élaboration d’un
cahier des charges;
— servir de langage formel pour l’identification du contenu informationnel commun à diverses
sources de données; en particulier pour faciliter l’implémentation d’algorithmes de transformation
automatique de données depuis des structures locales vers des structures universelles sans perte de
signification. Ces algorithmes de transformation sont utiles pour l’échange de données, la migration
de données depuis des systèmes existants, l’intégration des informations et l’interopérabilité de
sources de données hétérogènes;
— permettre l’interrogation associative de ressources intégrées en fournissant un modèle global des
classes de base et de leurs associations pour formuler de telles questions; et
— fournir à des concepteurs de systèmes d’information un guide de bonnes pratiques en modélisation
conceptuelle.
L’ontologie ISO 21127 est exprimée sous la forme d’une série de concepts en relation les uns avec les
autres, accompagnés de leurs définitions. Cette présentation est semblable à celle qui est en usage pour
un thésaurus. Cependant, cette ontologie n’est pas conçue comme une norme terminologique et ne vise
pas à définir les termes habituellement employés comme éléments de données dans la documentation
sur le patrimoine culturel. Bien que la présentation fournie ici soit complète, il s’agit d’une présentation
délibérément compacte et concise des 86 classes et 137 propriétés uniques dont l’ontologie se compose.
Elle ne cherche pas à expliciter sur l’ensemble de la hiérarchie des classes le fait que les sous-classes
héritent les propriétés de leurs super-classes (ce qui nécessiterait de déclarer plusieurs milliers de
1) Le Groupe d’Intérêt spécial pour le CIDOC CRM continue de mettre à jour une version de ce document original,
usuellement dénommé «Modèle conceptuel de référence du CIDOC» ou CIDOC CRM.
2) Dans le sens où le terme est employé en informatique, c’est-à-dire la description dans un langage formel des
concepts explicites et implicites pertinents et des relations qui existent entre eux.
propriétés, contre seulement 137). Cependant, cette définition contient bien toute l’information requise
pour inférer et générer automatiquement une déclaration complète de toutes les propriétés, y compris
les propriétés héritées.
vi © ISO 2014 – Tous droits réservés
NORME INTERNATIONALE ISO 21127:2014(F)
Information et documentation — Une ontologie de
référence pour l’échange d’informations du patrimoine
culturel
1 Domaine d’application
La présente Norme internationale fixe des lignes directrices pour l’échange d’informations entre
institutions patrimoniales. En termes simples, on peut dire qu’il s’agit de l’information gérée par les
musées, les bibliothèques et les archives.
Une définition plus détaillée peut être formulée en définissant le domaine d’application envisagé, une
définition large et inclusive basée sur des principes généraux, et le domaine d’application pratique, qui
est défini par référence à un ensemble de normes et de pratiques de documentation propres aux musées.
Le domaine d’application visé par la présente Norme internationale porte sur l’échange et l’intégration
de la documentation scientifique hétérogène relative aux collections muséales. Cette définition appelle
un développement.
— Le terme «documentation scientifique» vise à exprimer le fait que les informations descriptives
susceptibles d’être concernées par la présente Norme internationale doivent être d’une exhaustivité
et d’une qualité suffisantes à des fins de recherche universitaire sérieuse. Cela ne signifie pas pour
autant que des informations destinées à être présentées au grand public sont exclues, mais plutôt
que la présente Norme internationale vise à fournir le niveau de détail et de précision attendu et
exigé par les professionnels des musées et les chercheurs du domaine.
— Le terme «collections muséales» vise à recouvrir tous types d’objets rassemblés et exposés par
3)
les musées et institutions apparentées, selon la définition de l’ICOM , ce qui inclut des collections,
des sites et des monuments en lien avec des domaines tels que l’histoire sociale, l’ethnographie,
l’archéologie, les beaux-arts et les arts appliqués, l’histoire naturelle, l’histoire des sciences et des
techniques.
— La documentation des collections comprend la description détaillée d’objets individuels au sein des
collections, de groupes d’objets et des collections considérées comme un tout. La présente Norme
internationale vise spécifiquement à couvrir des informations contextuelles (c’est-à-dire l’arrière-
plan historique, géographique et théorique qui confère aux collections muséales une bonne part de
leur importance et de leur valeur culturelles).
— L’échange des informations pertinentes avec les bibliothèques et les archives et l’harmonisation avec
leurs modèles entre dans le domaine d’application envisagé de la présente Norme internationale.
— Les informations qui ne sont requises que pour l’administration et la gestion des institutions
culturelles, telles que les informations concernant la gestion du personnel, la comptabilité et les
statistiques de fréquentation, échappent au domaine d’application envisagé de la présente Norme
internationale.
4)
Le domaine d’application pratique de la présente Norme internationale est l’ensemble des normes de
référence pour la documentation muséographique qui ont servi à en guider et en valider l’élaboration. La
présente Norme internationale couvre le même domaine de discours que l’ensemble de ces documents
de référence; par conséquent, pour toute donnée correctement encodée selon n’importe lequel de ces
3) Les statuts de l’ICOM offrent une définition du terme «musée» à l’adresse:
html#2>.
4) Le domaine d’application pratique du CIDOC CRM, avec une liste des normes pertinentes en documentation
muséographique, est présenté de façon plus détaillée sur le site Web du CIDOC CRM, à l’adresse
org/scope.html>.
documents de référence, il est possible de créer une forme d’encodage qui soit compatible avec la norme
actuelle et en même temps n’entraîne aucune perte sémantique.
2 Conformité
Il convient que les utilisateurs qui ont l’intention de mettre à profit l’interopérabilité sémantique
offerte par la présente Norme internationale s’assurent de la conformité avec les structures de données
concernées. La conformité porte sur les données à rendre accessibles dans un environnement intégré ou
qui sont destinées à être transférées vers d’autres environnements. Tout encodage de données dans un
langage formel qui préserve les relations entre les classes, les propriétés et les règles d’héritage définies
par la présente Norme internationale, est considéré comme conforme.
La conformité à la présente Norme internationale n’exige ni une correspondance complète de toutes les
structures de documentation locales, ni que tous les concepts et les structures définis par la présente
Norme internationale soient mis en œuvre. La présente Norme internationale est élaborée pour
permettre les extensions nécessaires pour recouvrir toute la richesse des informations culturelles,
aussi bien que les simplifications, pour des raisons d’économie. Un système sera considéré comme
partiellement conforme s’il prend en compte un sous-ensemble de classes et de propriétés définies par
la présente Norme internationale. Il convient que les concepteurs du système publient les détails des
éléments qui sont pris en compte.
La présente Norme internationale se concentre sur l’échange et l’interopérabilité d’informations
structurées. Elle ne contraint pas à transformer des informations non structurées (en texte libre) en un
formalisme structuré et logique. Les informations en texte libre sont prises en compte, mais n’entrent
pas dans le champ d’application de ces considérations sur la conformité.
Tout système de documentation sera jugé conforme à la présente Norme internationale, indépendamment
de la structure interne de données qu’il emploie, s’il est possible de construire un algorithme logique
déterministe qui fait passer les données contenues dans le système à un formalisme directement
compatible sans perte de signification. Aucune supposition n’est faite quant à la nature de cet algorithme.
On entend par «sans perte de signification» le fait que les concepteurs et les utilisateurs du système
sont satisfaits de la correspondance de la représentation des données avec les définitions sémantiques
fournies par la présente Norme internationale.
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions suivants s’appliquent.
3.1
classe
catégorie d’entités qui partagent un ou plusieurs traits communs
Note 1 à l’article: Les traits d’une classe servent de critères pour l’identification des entités qui appartiennent
à cette classe. Ces traits n’ont pas besoin d’être explicitement formulés en termes logiques, mais peuvent être
décrits dans un texte (appelé ici une note d’application) qui fait référence à une conceptualisation commune aux
experts du domaine. La somme de ces traits est appelée l’intension de la classe. Une classe peut être le domaine
ou le codomaine de zéro, une seule ou plusieurs propriétés formellement définies dans un modèle. Les propriétés
formellement définies n’ont pas besoin de faire partie de l’intension de leur domaine ou de leur codomaine; de telles
propriétés sont facultatives. Une entité qui appartient à une classe est appelée une instance de cette classe. Une
classe est associée à un ensemble ouvert d’instances réelles, qui constituent l’extension de la classe. Ici, le terme
«ouvert» signifie que nous n’avons généralement pas la possibilité de connaître toutes les instances d’une classe
qui existent dans le monde, et qu’en fait il peut toujours apparaître de nouvelles instances dans l’avenir (notion
de monde ouvert). Une classe ne peut donc être définie par l’énumération de ses instances. Une classe joue un
rôle analogue à un substantif en grammaire, et peut être complètement définie sans faire référence à aucun autre
élément (à la différence des propriétés, qui doivent nécessairement avoir un domaine et un codomaine définis sans
ambiguïté). Par exemple, «Personne» est une classe. Une «Personne» peut avoir pour propriété d’être membre d’un
«Groupe», mais il ne s’agit pas là d’une condition nécessaire pour être une «Personne». Nous ne saurons jamais qui
sont toutes les «Personnes» qui ont vécu dans le passé, et de nouvelles «Personnes» apparaîtront dans l’avenir. Les
classes sont habituellement organisées en une hiérarchie de classes. La relation entre une sous-classe et sa super-
classe est appelée relation EstUn (la concaténation des mots «est un»). Par exemple, un bateau EstUn véhicule.
2 © ISO 2014 – Tous droits réservés
3.2
complément
〈d’une classe A〉 ensemble de toutes les instances de sa super-classe, B, qui ne sont pas des instances de A
Note 1 à l’article: Au sens de la théorie des ensembles, le complément d’une classe est l’extension de la super-
classe moins l’extension de la classe. Les extensions compatibles de la présente Norme internationale n’ont
pas besoin de déclarer une classe en tant que complément d’une ou de plusieurs autres classes. Cela entrerait
en contradiction avec l’objectif de décrire un monde ouvert. Par exemple, pour rendre compte de tous les cas
possibles d’appartenance d’un être humain à un sexe, il n’est pas nécessaire de déclarer «mâle» comme étant le
complément de «femelle» ou vice versa.
3.3
classes disjointes
n’ayant pas d’instances communes dans aucun monde possible
Note 1 à l’article: Deux classes sont disjointes si l’intersection de leurs extensions est nécessairement un ensemble
vide.
Note 2 à l’article: Voir aussi 5.4.
3.4
domaine
classe pour laquelle une propriété est formellement définie
Note 1 à l’article: Les instances d’une propriété sont applicables aux instances de sa classe de domaine. Une
propriété doit avoir exactement un domaine, bien que la classe de domaine puisse toujours contenir des instances
pour lesquelles la propriété n’est pas instanciée. La classe de domaine est analogue au sujet grammatical d’une
phrase, tandis que la propriété est analogue au verbe. La décision de déclarer telle classe comme domaine et telle
classe comme codomaine est arbitraire, de même que pour une phrase le choix entre voix active et voix passive est
arbitraire. Les noms des propriétés dans la norme ISO 21127 sont conçus pour être sémantiquement significatifs
et grammaticalement corrects [dans la version anglaise] quand ils sont lus du domaine vers le codomaine. Le nom
de propriété inverse, donné entre parenthèses, est également conçu pour être sémantiquement significatif et
grammaticalement correct [dans la version anglaise] quand il est lu du codomaine vers le domaine.
3.5
extension
ensemble de toutes les instances réelles d’une classe qui remplissent les critères de son intension
Note 1 à l’article: L’extension d’une classe est un ensemble «ouvert», en ce sens qu’il est, en général, impossible de
connaître toutes les instances d’une classe dans le monde. Il peut toujours apparaître de nouvelles instances dans
l’avenir (notion de monde ouvert). Un système d’information peut à tout instant ne faire référence qu’à quelques
instances d’une classe, qui forment un sous-ensemble de son extension.
Note 2 à l’article: Voir aussi 5.6.
3.6
héritage
duplication des propriétés d’une classe vers ses sous-classes
Note 1 à l’article: L’héritage de propriétés de super-classes vers les sous-classes implique que si une entité x est une
instance d’une classe A, alors toutes les propriétés qui doivent s’appliquer aux instances de n’importe laquelle des
super-classes de A doivent également s’appliquer à l’entité x, et que toutes les propriétés facultatives qui peuvent
s’appliquer aux instances de n’importe laquelle des super-classes de A peuvent également s’appliquer à l’entité x.
3.7
instance
entité ayant des propriétés qui remplissent les critères de l’intension de la classe
Note 1 à l’article: «La Joconde» est une instance de la classe E22 Objet Fabriqué. Une instance d’une propriété est
une relation factuelle entre une instance du domaine et une instance du codomaine de la propriété qui remplit
les critères de l’intension de la propriété. Par exemple, «le Louvre est propriétaire actuel de la Joconde» est une
instance de la propriété «est propriétaire actuel de». Il entre dans la définition du postulat de monde ouvert que
le nombre d’instances d’une classe déclarées dans un système d’information donné est habituellement inférieur
au nombre total des instances qui existent dans le monde réel. Par exemple, vous êtes une instance de «personne»,
mais vous ne figurez pas dans tous les systèmes d’information qui décrivent des «personnes».
3.8
intension
signification voulue d’une classe
Note 1 à l’article: L’intension d’une classe consiste en un ou plusieurs traits communs que partagent toutes les
instances de la classe. Ces traits n’ont pas besoin d’être explicitement formulés en termes logiques, mais peuvent
simplement être décrits dans un texte (une note d’application) qui renvoie à une conceptualisation que partagent
les experts du domaine.
3.9
interopérabilité
capacité des systèmes d’information à communiquer une partie de leur contenu
Note 1 à l’article: L’interopérabilité peut impliquer que:
a) deux systèmes peuvent échanger des informations; et/ou
b) on peut accéder à de multiples systèmes par une seule méthode.
Note 2 à l’article: En général, une distinction est établie entre interopérabilité syntaxique et interopérabilité
sémantique. L’interopérabilité syntaxique signifie que l’encodage de l’information et les protocoles d’accès des
systèmes concernés sont compatibles, de sorte que les informations puissent être traitées comme décrit ci-dessus
et sans erreurs. Cependant, l’interopérabilité syntaxique à elle seule ne garantit pas que chaque système traite
les données en cohérence avec la signification voulue. Par exemple, un système peut comporter une table appelée
«acteur» tandis qu’un autre système emploie le mot «agent». Bien que les données issues des deux tables puissent
être combinées dans un format de données commun, elles resteront néanmoins séparées tant que l’équivalence
sémantique de ces deux tables n’aura pas été établie. L’interopérabilité sémantique réclame plus que des formats
de données compatibles. La norme ISO 21127 présuppose l’existence d’une interopérabilité syntaxique et ne
s’occupe que d’y adjoindre une interopérabilité sémantique.
3.10
monotonique
〈d’une base de connaissances〉 ayant un ensemble de conclusions tirées par des règles d’inférence qui ne
diminue jamais, malgré l’addition de propositions supplémentaires
Note 1 à l’article: Le raisonnement monotonique est un terme emprunté à la représentation des connaissances.
En termes pratiques, au fur et à mesure que des experts entrent des déclarations correctes dans un système
d’information, le système n’a besoin de considérer aucune des déclarations préexistantes comme invalide.
L’ontologie de la norme ISO 21127 est conçue pour le raisonnement monotonique et permet donc la fusion sans
conflits de très grands fonds de connaissances.
Note 2 à l’article: Voir aussi 5.1.
4 © ISO 2014 – Tous droits réservés
3.11
héritage multiple
possibilité pour une classe d’avoir plus d’une super-classe directe
Note 1 à l’article: L’extension d’une classe ayant plusieurs super-classes directes est un sous-ensemble de
l’intersection de toutes les extensions de ses super-classes. L’intension d’une classe ayant plusieurs super-classes
directes élargit l’intension de toutes ses super-classes, c’est-à-dire que ses traits sont plus restrictifs que ceux de
n’importe laquelle de ses super-classes. Si l’héritage multiple est utilisé, la «hiérarchie de classes» qui en résulte
est un graphe dirigé et non pas une arborescence. Si elle est représentée sous forme de liste indentée, alors
certaines classes seront nécessairement répétées à différents endroits de la hiérarchie. Par exemple, «Personne»
est à la fois un «Agent» et un «Objet biologique».
3.12
monde ouvert
postulat selon lequel les informations stockées dans une base de connaissances sont incomplètes par
rapport à l’univers de discours qu’elle vise à décrire
Note 1 à l’article: Terme emprunté à la représentation des connaissances. Le caractère incomplet d’une base de
connaissances peut être dû à l’incapacité du gestionnaire à fournir des informations suffisantes, ou à des problèmes
cognitifs plus fondamentaux dans le domaine couvert par le système. De tels problèmes sont caractéristiques de
systèmes d’information culturels, puisque nos archives relatives au passé sont nécessairement incomplètes. De
plus, il peut exister des entités qui ne peuvent pas être assignées sans équivoque à une classe donnée. Notamment,
l’absence d’un certain trait pour une entité décrite par le système n’entraîne pas forcément que l’entité en question
ne possède pas ce trait. Par exemple, si une entité est décrite comme «objet biologique» et une autre comme
«objet matériel», il ne s’ensuit pas que cette dernière ne soit pas également un «objet biologique». On ne peut donc
pas, généralement, déduire les compléments d’une classe par rapport à une super-classe à partir d’un système
d’information fondé sur le postulat de monde ouvert.
3.13
concept primitif
concept qui est déclaré et dont la signification est connue, mais qui ne peut pas être dérivé à partir
d’autres concepts
Note 1 à l’article: Terme emprunté à la représentation des connaissances. Par exemple, mère peut se décrire comme
un être féminin qui a donné le jour à un enfant, il s’ensuit que mère n’est pas un concept primitif. En revanche,
Événement est un concept primitif. La norme ISO 21127 est composée en majeure partie de concepts primitifs.
3.14
propriété
caractéristique nommée d’une classe à laquelle peuvent être attribuées des valeurs
Note 1 à l’article: Une propriété est caractérisée par une intension, laquelle est exprimée au moyen d’une note
d’application. Une propriété joue un rôle analogue à un verbe en ce qu’elle doit être définie par référence à la fois à
un domaine et à un codomaine, lesquels sont analogues au sujet et à l’objet d’une phrase (contrairement aux classes,
qui peuvent être définies de façon indépendante). La décision de déclarer telle classe comme domaine et telle
classe comme codomaine est arbitraire, de même que pour une phrase le choix entre voix active et voix passive
est arbitraire. Autrement dit, une propriété peut être interprétée dans les deux sens, avec deux interprétations
qui sont distinctes mais liées. Par exemple, «E24 Chose Matérielle Fabriquée figure E1 Entité» est équivalent à
«E1 Entité est figuré sur E24 Chose Matérielle Fabriquée». Les propriétés peuvent elles-mêmes avoir des propriétés
qui pointent vers d’autres classes. (Cette caractéristique est utilisée dans le modèle uniquement pour décrire le
sous-typage dynamique des propriétés.) Les propriétés peuvent aussi être spécialisées de la même manière que les
classes, ce qui débouche sur des relations EstUn entre les sous-propriétés et leurs super-propriétés.
3.15
requête
recherche d’information sur un système d’information, exprimée de sorte que la réponse puisse être
calculée automatiquement
3.16
inclusion des requêtes
une requête X inclut une autre requête Y si, pour chaque population possible d’une base de données,
l’ensemble de réponses à la requête X contient aussi l’ensemble de réponses à la requête Y
Note 1 à l’article: Si les requêtes X et Y étaient des classes, X serait la super-classe d’Y.
3.17
codomaine
classe qui regroupe toutes les valeurs potentielles d’une propriété
Note 1 à l’article: La valeur d’une propriété à un instant donné est une instance de la classe désignée comme le
codomaine de la propriété. Une propriété est destinée à avoir une et une seule classe comme codomaine. On peut
établir une vague analogie entre la structure sujet-verbe-objet d’une proposition simple et la structure domaine-
propriété-codomaine définie dans la présente norme. La classe codomaine correspond à l’objet grammatical. La
décision de déclarer telle classe comme domaine et telle classe comme codomaine est arbitraire, de même que
pour une phrase le choix entre voix active et voix passive est arbitraire. Les noms des propriétés dans la norme
ISO 21127 sont conçus pour être sémantiquement significatifs et grammaticalement corrects [dans la version
anglaise] quand ils sont lus du domaine vers le codomaine. Le nom de propriété inverse, donné entre parenthèses,
est également conçu pour être sémantiquement significatif et grammaticalement correct [dans la version anglaise]
quand il est lu du codomaine vers le domaine.
3.18
note d’application
description textuelle de l’intension d’une classe ou d’une propriété
Note 1 à l’article: Les notes d’application ne sont pas des éléments de modélisation formels, mais sont fournies
dans le but de clarifier la signification voulue et l’application des classes et des propriétés. Fondamentalement,
elles renvoient à une conceptualisation partagée par les experts du domaine et éliminent des équivoques entre
différentes interprétations possibles. À titre d’illustration et d’explication, des exemples d’instances de classes et
de propriétés accompagnent les notes d’application.
3.19
raccourci
propriété formellement définie qui représente à elle seule une déduction ou une jointure d’un chemin de
données dans l’ontologie
Note 1 à l’article: Les notes d’application des propriétés définies comme des raccourcis donnent une description
verbale de la déduction équivalente. Les raccourcis sont présentés dans les cas où la pratique de documentation
habituelle renvoie seulement à la déduction plutôt qu’au chemin complet. Par exemple, les musées n’enregistrent
souvent que la «dimension» d’un objet sans documenter le E16 Mesurage qui l’a observée. La présente Norme
internationale permet des raccourcis dans les cas où les connaissances sont moins détaillées, tout en préservant
dans son schéma la relation avec l’information complète.
Note 2 à l’article: Voir aussi 5.3.
3.20
héritage strict
forme d’héritage de propriétés qui ne permet aucune exception
Note 1 à l’article: Certains systèmes peuvent déclarer que «les éléphants sont gris» et considérer un éléphant
blanc comme une exception. Selon des règles d’héritage strict, il serait établi que si tous les éléphants sont gris, un
éléphant blanc ne peut pas être un éléphant. Évidemment, tous les éléphants ne sont pas gris; être gris ne fait pas
partie de l’intension du concept d’éléphant, il s’agit d’une propriété facultative. La présente Norme internationale
applique l’héritage strict comme principe normatif.
6 © ISO 2014 – Tous droits réservés
3.21
sous-classe
spécialisation d’une autre classe, à savoir la super-classe
Note 1 à l’article: Une sous-classe hérite toutes les propriétés de sa super-classe (héritage strict), en plus des
propriétés (zéro, une ou plusieurs) qu’elle a par elle-même. Une sous-classe peut avoir plus d’une super-classe
directe et hérite par conséquent les propriétés de toutes ses super-classes (héritage multiple). Une sous-classe
a une relation EstUn avec sa ou ses super-classes: chaque instance de la sous-classe est aussi, par définition, une
instance de la ou des super-classes. Par exemple, chaque «personne» EstUn «objet biologique».
3.22
sous-propriété
spécialisation d’une autre propriété, à savoir la super-propriété
Note 1 à l’article: Toutes les instances d’une sous-propriété sont aussi des instances de sa super-propriété.
L’intension de la sous-propriété étend l’intension de sa super-propriété, c’est-à-dire que ses traits sont plus
restrictifs que ceux de sa super-propriété. Le domaine d’une sous-propriété est une sous-classe du domaine de sa
super-propriété. Le codomaine d’une sous-propriété est une sous-classe du codomaine de sa super-propriété. Les
instances d’une sous-propriété héritent, sans exception, la définition de toutes les propriétés déclarées pour sa
super-propriété (héritage strict), en plus des propriétés (zéro, une ou plusieurs) qu’elle a par elle-même.
Note 2 à l’article: Une sous-propriété peut avoir plus d’une super-propriété directe et hérite donc les propriétés de
toutes ses super-propriétés (héritage multiple). La relation EstUn, c’est à dire la spécialisation, de deux propriétés
ou plus, engendre la structure que nous appelons une hiérarchie de propriétés. La relation EstUn est transitive et ne
doit pas être cyclique. Dans certains langages orientés objet, dont C++, il n’y a aucun équivalent de la spécialisation
de propriétés.
3.23
super-classe
généralisation d’une ou de plusieurs autres classes, à savoir les sous-classes
Note 1 à l’article: Une super-classe subsume toutes les instances de ses sous-classes, et peut aussi avoir ses
propres instances qui n’appartiennent à aucune de ses sous-classes. L’intension de la super-classe est moins
restrictive que celle de n’importe laquelle de ses sous-classes. La relation de subsomption, ou généralisation, est
l’inverse de la relation EstUn, autrement dit, la spécialisation. Dans certains contextes (par exemple, le langage de
programmation C++), le terme classe parente est employé comme synonyme de super-classe. Par exemple, «objet
biologique subsume personne» est synonyme de «objet biologique est une super-classe de personne». Il faut moins
de propriétés pour identifier quelque chose en tant qu’«objet biologique» qu’en tant que «personne».
3.24
super-propriété
généralisation d’une ou de plusieurs autres propriétés, à savoir les sous-propriétés
Note 1 à l’article: Une super-propriété subsume toutes les instances de ses sous-propriétés, et peut aussi avoir ses
propres instances qui n’appartiennent à aucune de ses sous-propriétés. L’intension de la super-propriété est moins
restrictive que celle de n’importe laquelle de ses sous-propriétés. La relation de subsomption, ou généralisation, est
l’inverse de la relation EstUn, autrement dit, la spécialisation.
4 Structure et présentation
4.1 Quantificateurs des propriétés
Les quantificateurs des propriétés sont uniquement donnés dans un but de clarification sémantique
et il convient qu’ils ne soient pas traités comme des recommandations d’implémentation. La présente
Norme internationale a été élaborée pour permettre la cohabitation d’opinions divergentes et la
présence d’informations incomplètes; il convient donc que toutes les propriétés soient considérées lors
de l’implémentation comme facultatives et répétables pour leur domaine et leur codomaine [«plusieurs
vers plusieurs (0,n:0,n)»]. Le terme de «contraintes de cardinalité» est évité ici, dans la mesure où il
relève normalement des implémentations.
Le Tableau 1 énumère tous les quantificateurs possibles utilisés dans la présente Norme internationale
selon leur notation, accompagnés d’une explication textuelle. Afin d’arriver à une clarté optimale, deux
notations largement utilisées sont utilisées dans cette Norme internationale: une notation verbale et une
notation numérique. La notation verbale fait appel à des expressions telles que «un vers plusieurs», et la
notation numérique à des expressions telles que «(0,n:0,1)». Les termes «un», «plusieurs» et «nécessaire»
sont relativement intuitifs; le terme «dépendant» est moins immédiatement compréhensible. Il dénote
une situation où une instance de codomaine ne peut pas exister s’il n’existe pas une instance de la
propriété concernée. En d’autres termes, la propriété est «nécessaire» pour son codomaine.
Tableau 1 — Quantificateurs des propriétés
Quantificateur Description
plusieurs vers plu- Propriété non contrainte: toute instance du domaine et toute instance du codomaine
sieurs de la propriété peuvent avoir zéro, une ou plusieurs instances de cette propriété. En
d’autres termes, la propriété est facultative et répétable pour son domaine et pour son
(0,n:0,n)
codomaine.
un vers plusieurs Une instance du domaine de cette propriété peut avoir zéro, une ou plusieurs instances
de la propriété, mais une instance du codomaine ne peut pas recevoir plus d’une instance
(0,n:0,1)
de cette propriété. En d’autres termes, cette propriété est facultative pour son domaine
et pour son codomaine, mais n’est répétable que pour son domaine. Cette situation est
parfois appelée «en éventail».
plusieurs vers un Une instance du domaine de cette propriété peut avoir zéro ou une instance de la pro-
priété, mais une instance du codomaine peut recevoir zéro, une ou plusieurs instances
(0,1:0,n)
de la propriété. En d’autres termes, la propriété est facultative pour son domaine et pour
son codomaine, mais répétable uniquement pour son codomaine. Cette situation est par-
fois appelée «en entonnoir».
plusieurs vers plu- Une instance du domaine de cette propriété peut avoir une ou plusieurs instances de la
sieurs, nécessaire propriété, mais une instance du codomaine peut avoir zéro, une ou plusieurs instances
de la propriété. En d’autres termes, la propriété est nécessaire et répétable pour son
(1,n:0,n)
domaine, et facultative et répétable pour son codomaine.
un vers plusieurs, Une instance du domaine de cette propriété peut avoir une ou plusieurs instances de la
nécessaire propriété, mais une instance du codomaine ne peut pas recevoir plus d’une instance de la
propriété. En d’autres termes, la propriété est nécessaire et répétable pour son domaine,
(1,n:0,1)
et facultative mais non répétable pour son codomaine. Cette situation est parfois appelée
«en éventail».
plusieurs vers un, Une instance du domaine de cette propriété doit avoir exactement une instance de la pro-
nécessaire priété, mais une instance du codomaine peut recevoir zéro, une ou plusieurs instances
de la propriété. En d’autres termes, la propriété est nécessaire et non répétable pour
(1,1:0,n)
son domaine, et facultative et répétable pour son codomaine. Cette situation est parfois
appelée «en entonnoir».
un vers plusieurs, Une instance du domaine de cette propriété peut avoir zéro, une ou plusieurs instances
dépendant de la propriété, mais une instance du codomaine doit recevoir exactement une instance
de la propriété. En d’autres termes, la propriété est facultative et répétable pour son
(0,n:1,1)
domaine, mais nécessaire et non répétable pour son codomaine. Cette situation est par-
fois appelée «en éventail».
un vers plusieurs, Une instance du domaine de cette propriété peut avoir une ou plusieurs instances de la
nécessaire, dépen- propriété, mais une instance du codomaine doit recevoir exactement une instance de la
dant propriété. En d’autres termes, la propriété est nécessaire et répétable pour son domaine,
et nécessaire mais non répétable pour son codomaine. Cette situation est parfois appelée
(1,n:1,1)
«en éventail».
plusieurs vers un, Une instance du domaine de cette propriété doit avoir exactement une instance de la
nécessaire, dépen- propriété, mais une instance du codomaine peut recevoir une ou plusieurs instances de
dant cette propriété. En d’autres termes, la propriété est nécessaire et non répétable pour son
domaine, et nécessaire et répétable pour son codomaine. Cette situation est parfois appe-
(1,1:1,n)
lée «en entonnoir».
8 © ISO 2014 – Tous droits réservés
Tableau 1 (suite)
Quantificateur Description
un vers un Une instance du do
...
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