proposition: Lemma map_congr : forall f1 f2 l, (forall x, mem x l -> f1 x = f2 x) -> map f1 l = map f2 l.
proof: Proof. Proof using. introv H. induction l. { auto. } { do 2 rewrite map_cons. fequals. { applys H. applys mem_here. } { applys IHl. intros x Hx. applys H. applys* mem_next. } } Qed.
imports: Coq.Classes.Morphisms TLC(LibTactics LibLogic LibReflect LibOperation LibProd LibOption LibNat LibInt LibWf LibMonoid LibRelation)