∀ {α : Type u_1} (t' : Set (α × α)) (t : Set α) (x : α) (motive : (x_1 : α × α) → x_1 ∈ t ×ˢ {y | (x, y) ∈ t'} → Prop)
  (x_1 : α × α) (x_2 : x_1 ∈ t ×ˢ {y | (x, y) ∈ t'}),
  (∀ (a b : α) (x : (a, b) ∈ t ×ˢ {y | (x, y) ∈ t'}), motive (a, b) x) → motive x_1 x_2