category of fields
- notation:
- objects: fields
- morphisms: field homomorphisms (i.e., ring homomorphisms)
- Related categories:
- nLab Link
This is a typical example of a bad category of good objects.
Satisfied Properties
Properties from the database
- has connected limits
- has directed colimits
- has a generating set
- is inhabited
- is left cancellative
- is locally small
- is well-copowered
- is well-powered
Deduced properties
- has filtered colimits
- has equalizers
- has coreflexive equalizers
- is Cauchy complete
- has wide pullbacks
- has cofiltered limits
- has pullbacks
- is locally essentially small
- has reflexive coequalizers
- has sifted colimits
- has cosifted limits
- has sequential colimits
- has directed limits
- has sequential limits
Unsatisfied Properties
Properties from the database
- is not balanced
- does not have binary powers
- does not have a cogenerating set
- is not connected
- is not essentially small
- does not have a generator
- is not locally cartesian closed
- is not one-way
- does not have pushouts
- is not skeletal
Deduced properties*
- does not have a terminal object
- does not have finite products
- does not have products
- does not have binary products
- does not have countable products
- is not complete
- is not finitely complete
- does not have finite powers
- does not have countable powers
- does not have powers
- does not have biproducts
- does not have exact filtered colimits
- is not infinitary distributive
- is not distributive
- is not regular
- is not lextensive
- is not small
- is not finite
- is not essentially finite
- is not finitary algebraic
- is not a groupoid
- is not mono-regular
- is not direct
- is not thin
- does not have coequalizers
- does not have zero morphisms
- is not pointed
- does not have binary copowers
- is not discrete
- is not preadditive
- is not additive
- is not abelian
- is not Grothendieck abelian
- is not split abelian
- is not locally strongly finitely presentable
- is not essentially discrete
- is not trivial
- is not locally presentable
- is not locally finitely presentable
- is not locally ℵ₁-presentable
- is not cartesian closed
- is not an elementary topos
- does not have a subobject classifier
- does not have a regular subobject classifier
- is not a Grothendieck topos
- is not strongly connected
- is not Malcev
- is not unital
- does not have binary coproducts
- does not have finite coproducts
- does not have disjoint finite coproducts
- does not have disjoint coproducts
- is not extensive
- is not infinitary extensive
- does not have coproducts
- does not have an initial object
- does not have a strict initial object
- does not have countable coproducts
- is not cocomplete
- is not finitely cocomplete
- does not have connected colimits
- does not have wide pushouts
- does not have finite copowers
- does not have countable copowers
- does not have copowers
- does not have disjoint products
- does not have disjoint finite products
- is not infinitary codistributive
- is not codistributive
- does not have a strict terminal object
- is not coextensive
- is not infinitary coextensive
- is not coregular
- does not have a cogenerator
- is not right cancellative
- is not epi-regular
- is not inverse
- is not co-Malcev
- is not counital
- is not self-dual
*This also uses the deduced satisfied properties.
Unknown properties
—
Special objects
—
Special morphisms
- isomorphisms: bijective field homomorphisms
- monomorphisms: every morphism
- epimorphisms: purely inseparable homomorphisms
- regular monomorphisms: A Galois extension is a regular monomorphism iff it is procyclic, and the general case can be reduced to this situation; see the reference for details.
- regular epimorphisms: same as isomorphisms
Comments
- Limits and colimits are discussed in MSE/359352.