**Defined in theory: Frame-ontology****Source code: frame-ontology.lisp**

**Documentation:**If a SLOT-CARDINALITY of relation R with respect to a domain class C is N, then for all instances c of class C, R maps c to exactly N individuals in the range. For single-valued relations, the slot-cardinality is 1. Specifying a SLOT-CARDINALITY is a constraint between classes and binary-relations which does not always hold; there need not be any fixed value-cardinality for R on all instances of C.

**Arity:**3

(Nth-Domain Slot-Cardinality 3 Nonnegative-Integer) (Nth-Domain Slot-Cardinality 2 Binary-Relation) (Nth-Domain Slot-Cardinality 1 Class) (<=> (Slot-Cardinality ?Domain-Class ?Binary-Relation ?N) (=> (Instance-Of ?Instance ?Domain-Class) (= (Value-Cardinality ?Instance ?Binary-Relation) ?N)))

**See-Also:**Specifying that the slot cardinality is = to some integer is equivalent to using the Loom and CLASSIC `EXACTLY' operator.- Note that slot-cardinality is a function. That means that for any domain and relation, there is at most one integer N that can be the slot-cardinality. If there is no such fixed number, then the value of the function is undefined for the given domain and relation.