∀ {R S : CommRingCat} (f : R ⟶ S) (p : PrimeSpectrum ↑R),
  algebraMap ↑R
      ↑(((TopCat.Presheaf.pushforward CommRingCat (AlgebraicGeometry.Spec.topMap f)).obj
              (AlgebraicGeometry.Spec.structureSheaf ↑S).val).stalk
          p) =
    CommRingCat.Hom.hom (CategoryTheory.CategoryStruct.comp f (AlgebraicGeometry.StructureSheaf.toPushforwardStalk f p))