proposition: Lemma le_canonical_nS {n m pf} (H : le_canonical n m = left pf) : le_canonical n (S m) = left (le_S _ _ pf).
proof: Proof. simpl; rewrite H; reflexivity. Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat Coq.ZArith.ZArith Coq.Classes.Morphisms Coq.Program.Basics