proposition: Lemma Forall2_app : forall P r1 s1 r2 s2, Forall2 P r1 s1 -> Forall2 P r2 s2 -> Forall2 P (r1 ++ r2) (s1 ++ s2).
proof: Proof. Proof using. introv H H'. induction H; rew_list~. Qed.
imports: Coq.Classes.Morphisms TLC(LibTactics LibLogic LibReflect LibOperation LibProd LibOption LibNat LibInt LibWf LibMonoid LibRelation)