Relation Domain

Arity: 2
Definition-Sort-Index@Interface-Ontology: 100
DOMAIN is short for ``domain restriction''. A domain restriction of a binary relation is a constraint on the exact-domain of the relation. A domain restriction is superclass of the exact-domain; that is, all instances of the exact-domain of the relation are also instances of the DOMAIN restriction. Thus, the DOMAIN of a relation is not unique.

In an ontology, specifying a domain restriction of a binary relation is a way to specify partial information about the objects to which the relation applies. For example, one can state that favorite-beer is a relation from beer drinkers to beers as (domain favorite-beer person). This says that all people who have
a favorite-beer are instances of person, even though there may be some instances of person who do not have a favorite beer.

Representation systems can use these specifications to classify terms and check integrity constraints.


  • See-Also: In Cyc, domain is called makesSenseFor.

Domain: Binary-Relation
Binary-Relation, Binary-Relation, Relation, Relation, Relation ...
Inverse: Domain-Of
Range: Class

Implication Axioms for Domain:

(=> (Domain ?Relation ?Restriction)
    (Subclass-Of (Exact-Domain ?Relation) ?Restriction))

Equivalence Axioms for Domain:

(<=> (Domain ?Relation ?Restriction)
     (And (Binary-Relation ?Relation)
          (Class ?Restriction)
          (Subclass-Of (Exact-Domain ?Relation) ?Restriction)))

Axioms for Domain:

(Binary-Relation ?Relation)

Frame References to Domain:

In function Cardinality:

Domain: Set

In function Arity:

Domain: Relation

In relation Member:

Domain: Bounded

In relation Subclass-Partition:

Domain: Class

In function Cis:

Domain: Number

In function Day-Of@Simple-Time:

Domain: Time-Point@Simple-Time