The CIDOC CRM Format

1. The CIDOC CRM Format Martin Doerr Institute of Computer Science Foundation for Research and Technology - Hellas Heraklion - Crete Washington, Sept. 22, 1999

2. The CIDOC CRM Definitions • “Entity” is called anything like: • “class”, “entity” “node”, “individual” • comparable to tables, but with meaning • “link” is called anything like: • “attribute”, “reference”, ”link”, “property”, “relation” • comparable to table-column, but with a role meaning • “Entity and its subclass”is anything like: • “isA”, “subclass - superclass”, “derived class - parent class”, “generalization - specialization”

3. The CIDOC CRM Links • Links: • Optional (need not be instantiated) • Multivalued (e.g. “has author”!) • Strictly inherited (both sides !) • Can be specialized (see RDF:subproperty) • Can have links (to refine roles etc.) • can be implemented as entities if necessary...

4. The CIDOC CRMImplicit Metamodel • Entities are grouped by metaclasses ( “belongs to”) • Links are group by metacategories • like links between metacategories • The Metamodel serves as comment • But is formally correct • could be used to guide extensions of the model

5. The CIDOC CRMNaming Rules • Entities are named using initial capitals. • Entities are named using noun phrases (nominal group) • Links are named using lower case letters and are labeled in both directions. • Implementers can choose the appropriate part • Links are listed by priority at :Events, Objects, Actors,... • Links are named using verbal phrases, • states are named in present tense, • actions are named in past tense.

6. The CIDOC CRMScope Notes • A statement that clarifies the meaning and usage an Entity or link: • Definition by properties, not linguistic!! • Definition of scope - bounds and distinctions for the model • Context of usage, purpose and implicit view • Illustration by examples • Guidance to similar, overlapping, associated concepts

7. The CIDOC CRMFormat • Entity names (terms) are presented as headings in bold face, preceded by the arithmetic identifier. • The line “Belongs to:” refers to the metaclass, • The line “Subclass of:” declares the superclass of the entity, from which it inherits links • The line “Superclass of:” is a cross-reference to the following subclasses of this entity. • The line “Scope note” contains the textual definition of the concept the entity represents. • The title “Properties” announces the list of links. • Links are grouped by related meaning under metacategories, i.e. a series of titles as e.g. “classifications” etc., in normal face.

8. The CIDOC CRMFormat • Each link is represented by its forward and backward name, and the entity it links to, separated by colon. • Links declared directly for the entity are given in bold face. • Inherited links are given in italics as cross-references to the respective superclasses for better comprehension. • Inherited links with redefined (restricted ) target entity are given in bold face italics. • Each link may be followed by a scope note for the link in an indented text in smaller characters. • Links of links are given in an indented position in parenthesis under the respective link.

9. The CIDOC CRMFormat • The title “The entity is referenced by:” announces the cross-reference list of links pointing to this entity. • Each cross-link is represented by the entity it originates from, and its forward and backward name, separated by colon, and in normal face. • The title “The entity inherits references:” announces the cross-reference list of links pointing to any of the superclasses of this entity • Each inherited cross-link is represented by the entity it originates from, and its forward and backward name, separated by colon, and in italics.