∀ {J : Type u₁} [inst : CategoryTheory.Category.{v₁, u₁} J] {C : Type u₃} [inst_1 : CategoryTheory.Category.{v₃, u₃} C]
  (F : CategoryTheory.Functor J C) {X Y : CategoryTheory.CostructuredArrow (CategoryTheory.Functor.const J) F}
  (f : X ⟶ Y), ((CategoryTheory.Limits.Cone.fromCostructuredArrow F).map f).hom = f.left