#[global]
Hint Immediate Zpower_nat_is_exp Zpower_pos_is_exp : zarith.
#[global]
Hint Unfold Z.pow_pos Zpower_nat: zarith.

(* Specifications: *)
Theorem Zpower_exp x n m :
n >= 0 -> m >= 0 -> x ^ (n + m) = x ^ n * x ^ m.