∀ {C : Type u₁} {D : Type u₂} [inst : CategoryTheory.Category.{v₁, u₁} C] [inst_1 : CategoryTheory.Category.{v₂, u₂} D]
  [inst_2 : CategoryTheory.Preadditive C] [inst_3 : CategoryTheory.Preadditive D] {F : CategoryTheory.Functor C D}
  {G : CategoryTheory.Functor D C} (adj : F ⊣ G) [inst_4 : F.Additive] (X : C) (Y : D) (f : X ⟶ G.obj Y),
  (adj.homAddEquiv X Y).symm f = (adj.homEquiv X Y).symm f