English
A vector of length 1 corresponds to the single-element list with its head.
Русский
Вектор длины 1 соответствует односоставному списку, содержащему его голову.
LaTeX
$$$\forall v:\mathrm{Vector}\,\alpha\,1,\ v.toList = [v.head]$$$
Lean4
/-- The list that makes up a `Vector` made up of a single element,
retrieved via `toList`, is equal to the list of that single element. -/
@[simp]
theorem toList_singleton (v : Vector α 1) : v.toList = [v.head] :=
by
rw [← v.cons_head_tail]
simp only [toList_cons, toList_nil, head_cons, singleton_tail]