**Defined in ontology: Frame-ontology****Source pathname: /tmp_mnt/vol/q/htw/cms/ontolingua/examples/ontolingua/../../all-ontologies/ontolingua/frame-ontology.lisp**

**Arity:**2**Documentation:**A relation-universe of a relation of any arity is a class from which is drawn every item in every tuple of the relation. Like EXACT-DOMAIN, it is exactly those items and no other. Thus, to state that the universe of a relation is covered by some class, one can state that the relation-universe is a subclass of the covering class.

### Notes:

**See-Also:**universe- version 4: Added.

**Domain:**Relation**Instance-Of:**- Binary-Relation, Function,
*Relation*,*Set* **Range:**Class

(<=> (Relation-Universe ?Relation) (And (Relation ?Relation) (Class ?Type-Class) (Forall (?X) (<=> (Exists (?Tuple) (And (Member ?Tuple ?Relation) (Item ?X ?Tuple))) (Instance-Of ?X ?Type-Class)))))

(=> (= (Relation-Universe ?Relation) ?Type-Class) (Forall (?X) (<=> (Exists (?Tuple) (And (Member ?Tuple ?Relation) (Item ?X ?Tuple))) (Instance-Of ?X ?Type-Class)))) (=> (= (Relation-Universe ?Relation) ?Type-Class) (Class ?Type-Class)) (=> (= (Relation-Universe ?Relation) ?Type-Class) (Relation ?Relation))