∀ {α : Type u_1} {l : List α} [inst : Preorder α],
  (∀ (i : ℕ) (h : i < l.length) (i_1 : ℕ) (h_1 : i_1 < l.length),
      ⟨i, h⟩ < ⟨i_1, h_1⟩ → l.get ⟨i_1, h_1⟩ ≤ l.get ⟨i, h⟩) ↔
    List.Pairwise (fun x1 x2 => x2 ≤ x1) l