∀ {P P' : TopCat → Prop} (h : ∀ (X : CompHausLike P), P X.toTop → P' X.toTop) {X Y Z : CompHausLike P} (f : X ⟶ Y)
  (g : Y ⟶ Z),
  CategoryTheory.ConcreteCategory.ofHom (TopCat.Hom.hom (CategoryTheory.CategoryStruct.comp f g).hom) =
    CategoryTheory.CategoryStruct.comp (CategoryTheory.ConcreteCategory.ofHom (TopCat.Hom.hom f.hom))
      (CategoryTheory.ConcreteCategory.ofHom (TopCat.Hom.hom g.hom))