Being an isomorphism is local at the target #
theorem
AlgebraicGeometry.isomorphisms_eq_stalkwise :
CategoryTheory.MorphismProperty.isomorphisms AlgebraicGeometry.Scheme = (CategoryTheory.MorphismProperty.isomorphisms TopCat).inverseImage AlgebraicGeometry.Scheme.forgetToTop ⊓ AlgebraicGeometry.stalkwise fun {R S : Type u_1} [CommRing R] [CommRing S] (f : R →+* S) => Function.Bijective ⇑f