∀ {X Y Z : AlgebraicGeometry.Scheme} (f : X ⟶ Y) (g : Y ⟶ Z) {Z_1 : CommRingCat}
  (h : X.presheaf.obj (Opposite.op ⊤) ⟶ Z_1),
  CategoryTheory.CategoryStruct.comp (AlgebraicGeometry.Scheme.Hom.appTop (CategoryTheory.CategoryStruct.comp f g)) h =
    CategoryTheory.CategoryStruct.comp (AlgebraicGeometry.Scheme.Hom.appTop g)
      (CategoryTheory.CategoryStruct.comp (AlgebraicGeometry.Scheme.Hom.appTop f) h)