English
For all a,b and n, replicate(n, a) = replicate(n, b) iff n = 0 or a = b.
Русский
Для любых a,b и n: replicate(n, a) = replicate(n, b) эквивалентно n = 0 или a = b.
LaTeX
$$$$\\forall a,b:\\\\alpha,\\\\forall n:\\\\mathbb{N},\\\\ replicate(n,a) = replicate(n,b) \\\\iff n = 0 \\\\lor a = b.$$$$
Lean4
theorem replicate_right_inj' {a b : α} : ∀ {n}, replicate n a = replicate n b ↔ n = 0 ∨ a = b
| 0 => by simp
| n + 1 => (replicate_right_inj n.succ_ne_zero).trans <| by simp only [n.succ_ne_zero, false_or]