English
For any a ∈ α and n ∈ ℤ, a^{-1} ^ n = (a^{n})^{-1}.
Русский
Для любого a ∈ α и n ∈ ℤ, a^{-1} ^ n = (a^{n})^{-1}.
LaTeX
$$$a^{-1} ^ n = (a^{n})^{-1}$$$
Lean4
@[to_additive (attr := simp) neg_zsmul]
theorem zpow_neg (a : α) : ∀ n : ℤ, a ^ (-n) = (a ^ n)⁻¹
| (_ + 1 : ℕ) => DivInvMonoid.zpow_neg' _ _
| 0 => by simp
| Int.negSucc n => by
rw [zpow_negSucc, inv_inv, ← zpow_natCast]
rfl