{α : Type u_1} →
  {β : α → Type u_2} →
    (motive : Sigma β → Sigma β → Sort u_3) →
      (x x_1 : Sigma β) → ((a₁ : α) → (b₁ : β a₁) → (a₂ : α) → (b₂ : β a₂) → motive ⟨a₁, b₁⟩ ⟨a₂, b₂⟩) → motive x x_1