(<- (Generalized-Intersection ?Set-Of-Sets) (Setofall ?X (Exists (?S) (=> (Member ?S ?Set-Of-Sets) (Member ?X ?S))))) (=> (Generalized-Intersection $X $Y) (Set $Y)) (=> (Generalized-Intersection $X $Y) (Set $X)) (=> (= (Generalized-Intersection ?Set-Of-Sets) ?Set) (Forall (?S) (=> (Member ?S ?Set-Of-Sets) (Simple-Set ?S))))