CatDat

category of schemes

Satisfied Properties

Properties from the database

Deduced properties

Unsatisfied Properties

Properties from the database

Deduced properties*

*This also uses the deduced satisfied properties.

Unknown properties

There are 9 properties for which the database doesn't have an answer if they are satisfied or not. Please help to contribute the data!

Special objects

  • terminal object: Spec(Z)\mathrm{Spec}(\mathbb{Z})
  • initial object: empty scheme
  • products: [finite case] The idea is to use Spec(A)×Spec(B)=Spec(AB)\mathrm{Spec}(A) \times \mathrm{Spec}(B) = \mathrm{Spec}(A \otimes B) and then to glue affine pieces together. See EGA I, Chap. I, Thm. 3.2.1.
  • coproducts: disjoint union with the product sheaf

Special morphisms

  • isomorphisms: pairs (f,f)(f,f^{\sharp}) consisting of a homeomorphism ff and an isomorphism of sheaves ff^{\sharp}
  • monomorphisms:
  • epimorphisms:
  • regular monomorphisms:
  • regular epimorphisms:

Comments

  • Monomorphisms are discussed at MO/56591. At least the case of morphisms of locally finite type is understood.
  • Regular monomorphisms are discussed at MO/66279.
  • Epimorphisms are discussed at MO/56564. Probably they cannot be classified.