∀ {α : Type u_1} (motive : List α → List α → List α → Sort u_2) (l₂ acc : List α)
  (h_1 : (l₂ acc : List α) → motive [] l₂ acc) (h_2 : (l₁ acc : List α) → motive l₁ [] acc)
  (h_3 : (x : α) → (xs : List α) → (y : α) → (ys acc : List α) → motive (x :: xs) (y :: ys) acc),
  (match [], l₂, acc with
    | [], l₂, acc => h_1 l₂ acc
    | l₁, [], acc => h_2 l₁ acc
    | x :: xs, y :: ys, acc => h_3 x xs y ys acc) =
    h_1 l₂ acc