**Defined in theory: Kif-sets****Source code: kif-sets.lisp**

**Documentation:**Two sets are identical if and only if they have the same members.

**Instance-Of:**Sentence**Defining-Axiom:**'(=> (And (Set ?S1) (Set ?S2)) (<=> (Forall (?X) (<=> (Member ?X ?S1) (Member ?X ?S2))) (= ?S1 ?S2)))

**Source:**KIF Version 3.0 Specification