English
For p ∈ ℚ and n ∈ ℕ, the cast of p^n equals (p^n) cast in α.
Русский
Для p ∈ ℚ и n ∈ ℕ приводение p^n в α даёт тот же результат, что и (p^n) в α.
LaTeX
$$$\forall p \in \mathbb{Q}, \forall n \in \mathbb{N},\ ↑(p^n) = (p^n : \alpha).$$$
Lean4
/-- If monoid with zero homs `f` and `g` from `ℚ≥0` agree on the naturals then they are equal. -/
theorem ext_nnrat' (h : ∀ n : ℕ, f n = g n) : f = g :=
(DFunLike.ext f g) fun r =>
by
rw [← r.num_div_den, div_eq_mul_inv, map_mul, map_mul, h, eq_on_inv₀ f g]
apply h