English
In a topological monoid M with continuous multiplication, for every natural number n, the map a ↦ a^n is continuous.
Русский
В топологическом моноиде M с непрерывным умножением для каждого натурального числа n отображение a ↦ a^n непрерывно.
LaTeX
$$$\\forall n \\in \\mathbb{N},\\; \\text{Continuous}(a \\mapsto a^n)$$$
Lean4
@[to_additive (attr := continuity)]
theorem continuous_pow : ∀ n : ℕ, Continuous fun a : M => a ^ n
| 0 => by simpa using continuous_const
| k + 1 => by
simp only [pow_succ']
exact continuous_id.mul (continuous_pow _)