Lemmas about Vector.extract #
extract #
theorem Vector.extract_push {n : Nat} {α : Type u_1} {xs : Vector α n} {b : α} {start stop : Nat} :
(xs.push b).extract start stop = if h₁ : stop ≤ n then Vector.cast ⋯ (xs.extract start stop)
else if h₂ : start ≤ n then Vector.cast ⋯ ((xs.extract start).push b) else Vector.cast ⋯ #v[]