English
For any a ∈ α and n,m ∈ ℕ, n times replicating m copies of a equals replicating n·m copies of a: n · replicate m a = replicate (n·m) a.
Русский
Для любого a ∈ α и n,m ∈ ℕ n-кратно повторяем m копий элемента a дает replicate (n·m) копий a: n · replicate m a = replicate (n·m) a.
LaTeX
$$$n \cdot \mathrm{replicate}(m,a) = \mathrm{replicate}(n\cdot m,a).$$$
Lean4
theorem nsmul_replicate {a : α} (n m : ℕ) : n • replicate m a = replicate (n * m) a :=
((replicateAddMonoidHom a).map_nsmul _ _).symm