∀ {X : AlgebraicGeometry.Scheme} {U : X.Opens} {x : ↥X} (hxU : x ∈ U),
  AlgebraicGeometry.Scheme.Hom.app (X.fromSpecStalk x) U =
    CategoryTheory.CategoryStruct.comp (X.presheaf.germ U x hxU)
      (CategoryTheory.CategoryStruct.comp (AlgebraicGeometry.Scheme.ΓSpecIso (X.presheaf.stalk x)).inv
        ((AlgebraicGeometry.Spec (X.presheaf.stalk x)).presheaf.map (CategoryTheory.homOfLE ⋯).op))