{α : Type u_1} →
  {r : SetRel α α} →
    (p : RelSeries r) →
      (i : Fin (p.length + 1)) →
        (motive : Fin (p.length - ↑i + 1) → Sort u_2) →
          (x : Fin (p.length - ↑i + 1)) → ((j : ℕ) → (h : j < p.length - ↑i + 1) → motive ⟨j, h⟩) → motive x