English
For all n, the n-th iterate of Prod.map f g equals Prod.map (f^n) (g^n) (i.e., Nat.iterate).
Русский
Для любого n тождество: n-й повтор разложения Prod.map f g равен Prod.map (f^n) (g^n).
LaTeX
$$$\\operatorname{Nat.iterate}(\\\\operatorname{Prod.map} f g) n = \\\\operatorname{Prod.map}(\\\\operatorname{Nat.iterate} f n)(\\\\operatorname{Nat.iterate} g n).$$$
Lean4
@[simp]
theorem map_iterate (f : α → α) (g : β → β) (n : ℕ) : (Prod.map f g)^[n] = Prod.map f^[n] g^[n] := by
induction n <;> simp [*, Prod.map_comp_map]