category of pairs of sets
- notation:
- objects: pairs of sets and
- morphisms: A morphism consists of a map and a map .
- Related categories: ,
This is an example of the product of categories. It inherits most (but not all) properties from . It can also be seen as the category of sheaves on a discrete space with two points, and also as the slice category .
Satisfied Properties
Assigned properties
Deduced properties
- is locally finitely presentable
- is cocomplete
- is a generalized variety
- is regular
- is multi-algebraic
- is locally essentially small
- has coproducts
- is an elementary topos
- has a generating set
- has a cogenerator
- has exact filtered colimits
- is infinitary extensive
- is locally presentable
- is finitely accessible
- is accessible
- is locally ℵ₁-presentable
- is complete
- has sifted colimits
- is ℵ₁-accessible
- is locally finitely multi-presentable
- is multi-cocomplete
- has effective congruences
- is finitely complete
- has filtered colimits
- has filtered-colimit-stable monomorphisms
- has cartesian filtered colimits
- is extensive
- is cartesian closed
- has a subobject classifier
- has disjoint finite coproducts
- is epi-regular
- is finitely cocomplete
- is well-copowered
- is coregular
- is locally cartesian closed
- has connected colimits
- has coequalizers
- has a cogenerating set
- is inhabited
- has copowers
- has countable coproducts
- is well-powered
- is Cauchy complete
- is locally multi-presentable
- has connected limits
- has finite products
- has powers
- has pullbacks
- has equalizers
- has products
- is multi-complete
- has quotients of congruences
- is co-Malcev
- has effective cocongruences
- is mono-regular
- is Barr-exact
- has disjoint coproducts
- has finite coproducts
- is countably distributive
- is infinitary distributive
- has a strict initial object
- is filtered
- has directed colimits
- has reflexive coequalizers
- has a regular subobject classifier
- has a multi-initial object
- is cofiltered
- has sequential colimits
- is balanced
- has countable copowers
- has wide pushouts
- has a natural numbers object
- has countable powers
- has a multi-terminal object
- is distributive
- has coreflexive equalizers
- is sifted
- has an initial object
- has countable products
- has binary products
- has a terminal object
- has finite powers
- has wide pullbacks
- has coquotients of cocongruences
- is Barr-coexact
- is cosifted
- has cosifted limits
- has binary coproducts
- has finite copowers
- has pushouts
- is locally poly-presentable
- is connected
- has sequential limits
- has binary powers
- has cofiltered limits
- has binary copowers
- has cocartesian cofiltered limits
- has directed limits
Unsatisfied Properties
Assigned properties
- is not skeletal
- is not semi-strongly connected
- does not have a generator
Deduced properties*
- is not Grothendieck abelian
- is not strongly connected
- is not discrete
- does not have zero morphisms
- is not finitary algebraic
- is not thin
- is not gaunt
- is not direct
- is not inverse
- is not self-dual
- is not preadditive
- does not have biproducts
- is not right cancellative
- is not left cancellative
- does not have a strict terminal object
- is not trivial
- is not essentially discrete
- does not have kernels
- does not satisfy CIP
- is not a groupoid
- is not pointed
- is not normal
- is not subobject-trivial
- is not core-thin
- is not locally finite
- is not essentially small
- is not essentially countable
- is not essentially finite
- is not cocartesian coclosed
- does not have disjoint finite products
- does not have cokernels
- does not satisfy CSP
- is not conormal
- does not have a regular quotient object classifier
- is not quotient-trivial
- is not unital
- is not locally copresentable
- is not additive
- is not abelian
- is not small
- is not finite
- is not countable
- is not Malcev
- is not one-way
- does not have cofiltered-limit-stable epimorphisms
- is not counital
- is not locally cocartesian coclosed
- does not have disjoint products
- is not codistributive
- is not coextensive
- does not have a quotient object classifier
- is not split abelian
- is not coaccessible
- is not countably codistributive
- does not have exact cofiltered limits
- is not infinitary coextensive
- is not infinitary codistributive
*This also uses the deduced satisfied properties.
Unknown properties
—
Special objects
- terminal object:
- initial object:
- products: component-wise direct product
- coproducts: component-wise disjoint union
Special morphisms
- isomorphisms: pairs of bijective maps
- monomorphisms: pairs of injective maps
- epimorphisms: pairs of surjective maps
- regular monomorphisms: same as monomorphisms
- regular epimorphisms: same as epimorphisms