{v : Lean.Level} →
  {β : Q(Type v)} →
    {sβ : Q(CommSemiring «$β»)} →
      (motive : (a : Q(«$β»)) × Mathlib.Tactic.Ring.ExSum sβ a → Sort u_1) →
        (x : (a : Q(«$β»)) × Mathlib.Tactic.Ring.ExSum sβ a) →
          ((fst : Q(«$β»)) → (vb : Mathlib.Tactic.Ring.ExSum sβ fst) → motive ⟨fst, vb⟩) → motive x