{α : Sort u_3} →
  {β : α → Sort u_1} →
    (a : α) →
      (motive : (b₁ b₂ : β a) → Decidable (b₁ = b₂) → Sort u_2) →
        (b₁ b₂ : β a) →
          (x : Decidable (b₁ = b₂)) →
            ((a_1 : β a) → motive a_1 a_1 (isTrue ⋯)) →
              ((x x_1 : β a) → (n : ¬x = x_1) → motive x x_1 (isFalse n)) → motive b₁ b₂ x