Proof (eqmod_mult modulus).
Hint Resolve eqm_mult: ints.
(** ** Properties of the coercions between [Z] and [int] *)

(* Specifications: *)
Lemma eqm_samerepr: forall x y, eqm x y -> repr x = repr y.
Lemma eqm_unsigned_repr:
forall z, eqm z (unsigned (repr z)).