∀ {C : Type u₁} [inst : CategoryTheory.Category.{v₁, u₁} C] {D : Type u₂} [inst_1 : CategoryTheory.Category.{v₂, u₂} D]
  {B : Type u₄} [inst_2 : CategoryTheory.Category.{v₄, u₄} B] (S : D) (F : CategoryTheory.Functor B C)
  (G : CategoryTheory.Functor C D) (X : CategoryTheory.Comma (CategoryTheory.Functor.fromPUnit S) (F.comp G)),
  ((CategoryTheory.StructuredArrow.pre S F G).obj X).hom = X.hom