Module Type NZOrderProp
(Import NZ : NZOrdSig')(Import NZBase : NZBaseProp NZ).
Instance le_wd : Proper (eq==>eq==>iff) le.
Ltac le_elim H := rewrite lt_eq_cases in H; destruct H as [H | H].

Theorem le_succ_l : forall n m, S n <= m <-> n < m.