∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.Abelian C] {X Y : C}
  (R : CategoryTheory.InjectiveResolution Y) {n : ℕ} (f : X ⟶ R.cocomplex.X n) (m : ℕ),
  CategoryTheory.CategoryStruct.comp f (R.cocomplex.d n m) = 0 →
    CategoryTheory.CategoryStruct.comp (-f) (R.cocomplex.d n m) = 0