Module Type NSubProp (Import N : NAxiomsMiniSig').
Include NMulOrderProp N.
(* This could be proved by adding m to both sides. Then the proof would use add_sub_assoc and sub_0_le, which is proven below. *)
(** Sub and order *)

Theorem sub_0_le : forall n m, n - m == 0 <-> n <= m.