proposition: Lemma Zpower_nat_is_exp : forall (n m:nat) (z:Z), Zpower_nat z (n + m) = Zpower_nat z n * Zpower_nat z m.
proof: Proof. intros n; induction n as [|n IHn]. - intros. now rewrite Zpower_nat_0_r, Z.mul_1_l. - intros. simpl. now rewrite IHn, Z.mul_assoc. Qed.
imports: Wf_nat ZArith_base Zcomplements Zpow_def