English
Similarly, snd i (prod.mk i a b) = b for all i, with the result proven by induction on i.
Русский
Аналогично, snd i (prod.mk i a b) = b для любого i, доказательство идёт по индукции по i.
LaTeX
$$$\\mathrm{snd}(\\mathrm{prod.mk}\ i\ a\ b) = b$.$$
Lean4
@[simp]
theorem prod_snd_mk {α β : TypeVec n} (i : Fin2 n) (a : α i) (b : β i) : TypeVec.prod.snd i (prod.mk i a b) = b := by
induction i with
| fz => simp_all [prod.snd, prod.mk]
| fs _ i_ih => apply i_ih