∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.Abelian C] {Y Z : C}
  {I : CategoryTheory.InjectiveResolution Y} {J : CategoryTheory.InjectiveResolution Z} (f : I.cocomplex ⟶ J.cocomplex)
  (comm : CategoryTheory.CategoryStruct.comp I.ι f = 0) {Z_1 : C} (h : J.cocomplex.X 1 ⟶ Z_1),
  CategoryTheory.CategoryStruct.comp (I.cocomplex.d 1 2)
      (CategoryTheory.CategoryStruct.comp (CategoryTheory.InjectiveResolution.descHomotopyZeroOne f comm) h) =
    CategoryTheory.CategoryStruct.comp
      (f.f 1 -
        CategoryTheory.CategoryStruct.comp (CategoryTheory.InjectiveResolution.descHomotopyZeroZero f comm)
          (J.cocomplex.d 0 1))
      h