category of schemes
- Notation:
- Objects: schemes over , i.e. locally ringed spaces over that have an open covering by affine schemes over
- Morphisms: morphisms of locally ringed spaces over
- Related categories: ,
- nLab Link
Here, is a fixed non-trivial commutative ring. The general properties of this category will not depend on the choice of . For we obtain the category of schemes.
Satisfied Properties
Assigned properties
- is locally small
- has a terminal object
- has pullbacks
- is well-powered
- is infinitary extensive
Deduced properties
- is connected
- has a multi-terminal object
- has coproducts
- is extensive
- is ℵ₁-filtered
- has binary products
- is locally essentially small
- is inhabited
- has equalizers
- has finite coproducts
- has disjoint finite coproducts
- has a strict initial object
- is filtered
- has finite products
- has binary powers
- has copowers
- has ℵ₂-small coproducts
- is finitely complete
- has disjoint coproducts
- has coreflexive equalizers
- is Cauchy complete
- is distributive
- is infinitary distributive
- is sifted
- has an initial object
- has finite powers
- is cosifted
- has countable coproducts
- has ℵ₂-small copowers
- has binary coproducts
- has finite copowers
- is countably distributive
- has a multi-initial object
- has coquotients of cocongruences
- is cofiltered
- is ℵ₁-cofiltered
- has countable copowers
- has binary copowers
- has a natural numbers object
Unsatisfied Properties
Assigned properties
- is not skeletal
- is not balanced
- does not have countable powers
- is not Malcev
- is not semi-strongly connected
- does not have a generating set
- does not have quotients of congruences
- does not have sequential colimits
Deduced properties*
- is not thin
- is not additive
- is not cartesian closed
- does not have reflexive coequalizers
- is not core-thin
- is not strongly connected
- is not discrete
- does not have a generator
- does not have an extremal generating set
- is not mono-regular
- does not have countable products
- does not have ℵ₂-small powers
- does not have sequential limits
- is not gaunt
- is not direct
- is not a Grothendieck topos
- does not have directed colimits
- does not have coequalizers
- is not inverse
- is not epi-regular
- is not self-dual
- is not accessible
- is not preadditive
- is not abelian
- is not Grothendieck abelian
- is not left cancellative
- is not locally cartesian closed
- does not have effective congruences
- does not have zero morphisms
- is not core-connected
- is not trivial
- is not essentially discrete
- does not have a strict terminal object
- is not subobject-trivial
- is not one-way
- does not have filtered colimits
- does not have directed limits
- does not have sifted colimits
- does not have an extremal generator
- is not a groupoid
- is not normal
- does not have ℵ₂-small products
- does not have powers
- is not essentially small
- does not have a subobject classifier
- is not regular-subobject-trivial
- is not essentially finite
- is not an elementary topos
- is not right cancellative
- is not cocartesian coclosed
- is not cocomplete
- is not finitely cocomplete
- does not have disjoint finite products
- is not countably codistributive
- does not have pushouts
- is not quotient-trivial
- is not conormal
- does not have connected colimits
- does not have a quotient object classifier
- does not have a regular quotient object classifier
- is not locally finite
- is not essentially countable
- is not pointed
- is not locally finitely presentable
- is not locally ℵ₁-presentable
- is not locally presentable
- is not ℵ₁-accessible
- is not finitely accessible
- is not locally strongly finitely presentable
- is not locally multi-presentable
- is not locally poly-presentable
- is not split abelian
- does not have biproducts
- is not a generalized variety
- is not multi-algebraic
- is not Barr-exact
- does not have kernels
- does not have exact filtered colimits
- does not have cartesian filtered colimits
- does not have filtered-colimit-stable monomorphisms
- does not satisfy CIP
- is not finitary algebraic
- does not have products
- is not small
- is not finite
- is not countable
- is not regular-quotient-trivial
- is not a quasitopos
- is not co-Malcev
- is not counital
- is not locally copresentable
- is not locally cocartesian coclosed
- does not have wide pushouts
- is not multi-cocomplete
- is not coregular
- does not have disjoint products
- is not infinitary codistributive
- is not codistributive
- does not have cokernels
- does not have exact cofiltered limits
- does not satisfy CSP
- is not coextensive
- does not have cofiltered limits
- is not unital
- is not locally finitely multi-presentable
- is not complete
- does not have wide pullbacks
- is not a pretopos
- is not Barr-coexact
- does not have cocartesian cofiltered limits
- does not have cofiltered-limit-stable epimorphisms
- is not infinitary coextensive
- does not have cosifted limits
- is not multi-complete
- does not have connected limits
*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!
- is coaccessible
- has a cogenerating set
- has a cogenerator
- has effective cocongruences
- has an extremal cogenerating set
- has an extremal cogenerator
- is regular
- has a regular subobject classifier
- is well-copowered
- has ℵ₁-cofiltered limits
- has ℵ₁-filtered colimits
Special objects
- terminal object:
- initial object: empty scheme
- products: [finite case] The idea is to use 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 consisting of a homeomorphism and an isomorphism of sheaves of -algebras
- monomorphisms:
- epimorphisms:
- regular monomorphisms:
- regular epimorphisms: