End Zabs2N.
(** * Conversions between [Z] and [nat] *)
Module Nat2Z.
(** [Z.of_nat], basic equations *)

(* Specifications: *)
Lemma inj_0 : Z.of_nat 0 = 0.
Lemma inj_succ n : Z.of_nat (S n) = Z.succ (Z.of_nat n).
Register inj_succ as num.Nat2Z.inj_succ.