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
- is 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 sifted
- 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
- 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 accessible
- 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
- is not mono-regular
- does not have countable products
- does not have ℵ₂-small powers
- does not have sequential limits
- is not essentially small
- 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 locally presentable
- is not ℵ₁-accessible
- is not locally multi-presentable
- is not locally poly-presentable
- is not preadditive
- is not abelian
- is not Grothendieck abelian
- is not right cancellative
- is not left cancellative
- is not locally cartesian closed
- does not have effective congruences
- does not have zero morphisms
- 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
- is not finitary algebraic
- is not a groupoid
- is not normal
- does not have ℵ₂-small products
- does not have powers
- is not small
- is not essentially countable
- does not have a subobject classifier
- is not essentially finite
- is not an elementary topos
- 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 pointed
- is not locally finitely presentable
- is not locally ℵ₁-presentable
- is not finitely accessible
- is not locally strongly finitely 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
- does not have products
- is not finite
- is not countable
- 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 9 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
- 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: