English
For all m,n and a, replicate(m+n, a) = replicate(m, a) ++ replicate(n, a).
Русский
Для любых m,n и a верно: replicate(m+n, a) = replicate(m, a) ++ replicate(n, a).
LaTeX
$$$$\\forall m\,\\forall n:\\\\mathbb{N},\\\\forall a:\\\\alpha, \\\\\\mathrm{replicate}(m+n, a) = \\\\\\mathrm{replicate}(m, a) \\\\\\append \\\\\\mathrm{replicate}(n, a).$$$$
Lean4
theorem replicate_add (m n) (a : α) : replicate (m + n) a = replicate m a ++ replicate n a := by
rw [replicate_append_replicate]