{X : SSet} →
  {A : X.Subcomplex} →
    {P : A.Pairing} →
      {α : Type v} →
        [inst : PartialOrder α] →
          {motive : P.WeakRankFunction α → Sort u_1} →
            (t : P.WeakRankFunction α) →
              ((rank : ↑P.II → α) →
                  (lt : ∀ {x y : ↑P.II}, P.AncestralRel x y → (↑x).dim = (↑y).dim → rank x < rank y) →
                    motive { rank := rank, lt := lt }) →
                motive t