{C : Type u₁} →
  [inst : CategoryTheory.Category.{v₁, u₁} C] →
    {X : C} →
      {motive : CategoryTheory.Sieve X → Sort u} →
        (t : CategoryTheory.Sieve X) →
          ((arrows : CategoryTheory.Presieve X) →
              (downward_closed :
                  ∀ {Y Z : C} {f : Y ⟶ X}, arrows f → ∀ (g : Z ⟶ Y), arrows (CategoryTheory.CategoryStruct.comp g f)) →
                motive { arrows := arrows, downward_closed := downward_closed }) →
            motive t