∀ (C : Type u₁) [inst : CategoryTheory.Category.{v₁, u₁} C] (D : Type u₂) [inst_1 : CategoryTheory.Category.{v₂, u₂} D]
  (F : CategoryTheory.Core (CategoryTheory.Functor C D)) {X Y : CategoryTheory.Core C} (f : X ⟶ Y),
  (((CategoryTheory.coreFunctor C D).obj F).map f).iso.hom = F.of.map f.iso.hom