(** (Mod a b n) means (a = b (mod n)) *)

Definition Mod (a b : Z) (n : nat) :=
  exists q : Z, a = (b + Z_of_nat n * q)%Z.

Lemma moda0_exp_compat : forall (a : Z) (n : nat), n > 0 -> Mod a 0 n -> forall m : nat, m > 0 -> Mod (Exp a m) 0 n.