∀ {α : Type u_1} [inst : PartialOrder α] (motive : (b a x : α) → x ∈ {a, b} → a ≤ b → Prop) (b a x : α)
  (x_1 : x ∈ {a, b}) (h : a ≤ b),
  (∀ (b x : α) (h : x ≤ b), motive b x x ⋯ h) → (∀ (x a : α) (h : a ≤ x), motive x a x ⋯ h) → motive b a x x_1 h