Section SubMemLaws.
Variable T : Type.
End ListMembership.
Prenex Implicits Mem_map_inv.
(* Setoids for extensional equality of functions *)

Lemma ImageIm A B C (f1 : B -> C) (f2 : A -> B) (X : Pred A) :
Image f1 (Image f2 X) =p Image (f1 \o f2) X.