{u : Lean.Level} →
  {arg : Q(Type u)} →
    {sα : Q(CommSemiring «$arg»)} →
      (motive : (b : Q(«$arg»)) → Mathlib.Tactic.Ring.ExSum sα b → Sort u_1) →
        (b : Q(«$arg»)) →
          (va₂ : Mathlib.Tactic.Ring.ExSum sα b) →
            (Unit → motive q(0) Mathlib.Tactic.Ring.ExSum.zero) →
              ((x : Q(«$arg»)) → (x_1 : Mathlib.Tactic.Ring.ExSum sα x) → motive x x_1) → motive b va₂