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

**Documentation:**One binary relation is the inverse of another if they are equivalent when their arguments are swapped.

**Arity:**2**Domain:**Binary-relation**Range:**Binary-relation

(<=> (Holds ?Binary-Relation ?X ?Y) (Holds (Inverse ?Binary-Relation) ?Y ?X)) (=> (Inverse ?Binary-Relation ?Inverse-Relation) (And (Binary-Relation ?Binary-Relation) (= ?Inverse-Relation (Setofall (Listof ?Y ?X) (Holds ?Binary-Relation ?X ?Y)))))

- Note that INVERSE is a function. It is possible to have more than one relation constant naming the inverse of a relation, but they are all = to each other.