English
IsRegular(a^n) iff IsRegular a for n > 0.
Русский
IsRegular(a^n) эквивалентно IsRegular a при n > 0.
LaTeX
$$$ IsRegular (a^n) \leftrightarrow IsRegular a \quad (0 < n) $$$
Lean4
/-- An element `a` is regular if and only if a positive power of `a` is regular. -/
@[to_additive]
theorem pow_iff {n : ℕ} (n0 : 0 < n) : IsRegular (a ^ n) ↔ IsRegular a
where
mp h := ⟨(IsLeftRegular.pow_iff n0).mp h.left, (IsRightRegular.pow_iff n0).mp h.right⟩
mpr h := ⟨.pow n h.left, .pow n h.right⟩