proposition: Lemma concat_last : forall l m, concat (m & l) = concat m ++ l.
proof: Proof. Proof using. intros. rewrite~ concat_app. rewrite~ concat_one. Qed.
imports: Coq.Classes.Morphisms TLC(LibTactics LibLogic LibReflect LibOperation LibProd LibOption LibNat LibInt LibWf LibMonoid LibRelation)