{n : ℤ} →
  {motive : CochainComplex.HomComplex.Triplet n → Sort u} →
    (t : CochainComplex.HomComplex.Triplet n) →
      ((p q : ℤ) → (hpq : p + n = q) → motive { p := p, q := q, hpq := hpq }) → motive t