∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] [inst_1 : CategoryTheory.HasShift C ℤ]
  {T₁ T₂ : CategoryTheory.Pretriangulated.Triangle C} [inst_2 : CategoryTheory.Preadditive C] {R : Type u_3}
  [inst_3 : Semiring R] [inst_4 : CategoryTheory.Linear R C]
  [inst_5 : ∀ (n : ℤ), (CategoryTheory.shiftFunctor C n).Additive]
  [inst_6 : ∀ (n : ℤ), CategoryTheory.Functor.Linear R (CategoryTheory.shiftFunctor C n)] (a : R) (x y : T₁ ⟶ T₂),
  a • (x + y) = a • x + a • y