proposition: Lemma fold_left_last : forall f i x l, fold_left f i (l & x) = f x (fold_left f i l).
proof: Proof. Proof using. intros. rewrite~ fold_left_app. Qed.
imports: Coq.Classes.Morphisms TLC(LibTactics LibLogic LibReflect LibOperation LibProd LibOption LibNat LibInt LibWf LibMonoid LibRelation)