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 11 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.