Module NZDomainProp (Import NZ:NZDomainSig').
Include NZBaseProp NZ.
(** * Relationship between points thanks to [succ] and [pred]. *)
(** For any two points, one is an iterated successor of the other. *)

Lemma itersucc_or_itersucc n m : exists k, n == (S^k) m \/ m == (S^k) n.