∀ {C : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} C] [inst_1 : CategoryTheory.Preadditive C]
  {S₁ S₂ : CategoryTheory.ShortComplex C} {φ φ' : S₁ ⟶ S₂} {h₁ : S₁.RightHomologyData} {h₂ : S₂.RightHomologyData}
  (γ : CategoryTheory.ShortComplex.RightHomologyMapData φ h₁ h₂)
  (γ' : CategoryTheory.ShortComplex.RightHomologyMapData φ' h₁ h₂), (γ.add γ').φH = γ.φH + γ'.φH