∀ {C : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} C] [inst_1 : CategoryTheory.Preadditive C] (n : ℕ)
  {X Y : CategoryTheory.SimplicialObject C} (f : X ⟶ Y),
  CategoryTheory.CategoryStruct.comp (f.app (Opposite.op (SimplexCategory.mk n)))
      (AlgebraicTopology.DoldKan.PInfty.f n) =
    CategoryTheory.CategoryStruct.comp (AlgebraicTopology.DoldKan.PInfty.f n)
      (f.app (Opposite.op (SimplexCategory.mk n)))