Contradict H; auto with zarith.
Qed.

(* Specifications: *)
Theorem OddMultInv : forall n m : Z, Odd (n * m) -> Odd n.
intros n m H; case (OddEvenDec n); auto; intros Z1.
Theorem EvenExp :
forall (n : Z) (m : nat), Even n -> Even (Zpower_nat n (S m)).