Module NAddProp (Import N : NAxiomsMiniSig').
Include NBaseProp N.
(** For theorems about [add] that are both valid for [N] and [Z], see [NZAdd] *)
(** Now comes theorems valid for natural numbers but not for Z *)

Theorem eq_add_0 : forall n m, n + m == 0 <-> n == 0 /\ m == 0.