intros e n m H' H'0.
case (Zle_or_lt m n); auto; intros Z1.
Contradict H'0.
apply Rle_not_lt.
apply Rle_powerRZ; auto.
Qed.

Theorem Zle_powerRZ :
forall (e : R) (n m : Z),
(1 < e)%R -> (powerRZ e n <= powerRZ e m)%R -> (n <= m)%Z.