∀ {C₁ : Type u₁} {C₂ : Type u₂} {C₃ : Type u₃} [inst : CategoryTheory.Category.{v₁, u₁} C₁]
  [inst_1 : CategoryTheory.Category.{v₂, u₂} C₂] [inst_2 : CategoryTheory.Category.{v₃, u₃} C₃]
  {G : CategoryTheory.Functor C₁ᵒᵖ (CategoryTheory.Functor C₃ C₂)} {f₁ : CategoryTheory.Arrow C₁}
  {f₃ f₃' : CategoryTheory.Arrow C₃} (sq₁₃ : G.PullbackObjObj f₁.hom f₃.hom) (sq₁₃' : G.PullbackObjObj f₁.hom f₃'.hom)
  (sq : f₃ ⟶ f₃'),
  (sq₁₃.mapArrowRight sq₁₃' sq).right =
    ⋯.lift (CategoryTheory.CategoryStruct.comp sq₁₃.fst ((G.obj (Opposite.op f₁.left)).map sq.left))
      (CategoryTheory.CategoryStruct.comp sq₁₃.snd ((G.obj (Opposite.op f₁.right)).map sq.right)) ⋯