{α : Type u_1} →
  {P : α → Prop} →
    (motive : (x : List α) → (∀ a ∈ x, P a) → Sort u_2) →
      (x : List α) →
        (x_1 : ∀ a ∈ x, P a) →
          ((x : ∀ a ∈ [], P a) → motive [] x) →
            ((a : α) → (l : List α) → (H : ∀ a_1 ∈ a :: l, P a_1) → motive (a :: l) H) → motive x x_1