proposition: Lemma curry_imset2r T U V (f : T -> U -> V) A1 A2 : f @2: (A1, A2) <--> \bigcup_(x2 in A2) f^~ x2 @: A1.
proof: Proof. by rewrite curry_imset2l bigcupC. Qed.
imports: mathcomp.ssreflect.ssreflect Classes.RelationClasses Classes.Morphisms List Tactics mathcomp(ssrfun ssrbool ssrnat seq)