category of finite sets and surjections
This category is badly behaved in itself, but it appears in representation theory. It has two connected components, consisting of the empty set and the non-empty finite sets.
Satisfied properties
Assigned properties
- is locally small
- is locally finite
- is essentially countable
- is right cancellative
- has coequalizers
- has wide pushouts
- is epi-regular
- has an extremal cogenerator
- is multi-complete
- is a generalized variety
- is finitely accessible
Deduced properties
- has filtered-colimit-stable monomorphisms
- is ℵ₁-accessible
- has filtered colimits
- has sifted colimits
- has effective congruences
- has a multi-terminal object
- is Cauchy complete
- is essentially small
- is locally essentially small
- is subobject-trivial
- is regular-subobject-trivial
- has cokernel pairs
- has reflexive coequalizers
- has a cogenerator
- has an extremal cogenerating collection
- is balanced
- has connected colimits
- has pushouts
- is accessible
- has ℵ₁-filtered colimits
- has quotients of congruences
- has directed colimits
- has an extremal generating collection
- is well-powered
- is mono-regular
- is retract-trivial
- is coaccessible
- is ℵ₁-coaccessible
- has a cogenerating collection
- is inhabited
- is well-copowered
- has pushout-stable regular monomorphisms
- has a generating collection
- has ℵ₁-cofiltered limits
- is locally multi-copresentable
- is locally poly-copresentable
- has sequential colimits
- is concretizable
- has coreflexive equalizers
- has effective cocongruences
- has coquotients of cocongruences
- has equalizers of cokernel pairs
Unsatisfied properties
Assigned properties
- is not small
- is not skeletal
- is not countable
- is not core-thin
- does not have a generator
- is not connected
- does not have sequential limits
- is not locally cocartesian coclosed
- does not have a multi-initial object
Deduced properties*
- is not Grothendieck abelian
- is not semi-strongly connected
- does not have kernels
- is not sifted
- does not have directed limits
- does not have an extremal generator
- is not finite
- is not thin
- is not gaunt
- is not direct
- is not one-way
- is not co-Grothendieck abelian
- is not multi-cocomplete
- does not have an initial object
- does not have disjoint products
- does not have cokernels
- is not cosifted
- is not a groupoid
- is not inverse
- is not an elementary cotopos
- is not a quasicotopos
- is not self-dual
- is not locally multi-presentable
- is not locally finitely multi-presentable
- is not abelian
- is not multi-algebraic
- is not strongly connected
- is not core-connected
- is not trivial
- is not discrete
- is not essentially discrete
- is not filtered
- does not have binary coproducts
- is not one-sorted finitary algebraic
- is not left cancellative
- is not pointed
- does not have a strict initial object
- does not have equalizers
- does not have binary copowers
- does not have countable powers
- does not have zero morphisms
- does not have powers
- does not have a conatural numbers object
- is not cocomplete
- is not countably coextensive
- is not cofiltered
- does not have binary products
- does not have cofiltered limits
- does not have finite coproducts
- does not have finite copowers
- is not preadditive
- is not regular-quotient-trivial
- does not have binary powers
- does not have countable copowers
- does not have copowers
- is not unital
- is not locally finitely presentable
- is not locally ℵ₁-presentable
- is not locally presentable
- is not finitary algebraic
- does not have connected limits
- is not additive
- is not split abelian
- does not have biproducts
- does not have kernel pairs
- is not finitely complete
- does not have disjoint finite coproducts
- is not distributive
- does not satisfy CIP
- is not extensive
- is not infinitary extensive
- is not finitely cocomplete
- is not ℵ₁-filtered
- is not normal
- does not have products
- does not have finite products
- does not have countable products
- does not have ℵ₂-small powers
- does not have finite powers
- does not have wide pullbacks
- is not total
- is not counital
- does not have a coparametrized conatural numbers object
- is not finitely coaccessible
- is not locally copresentable
- is not cocartesian coclosed
- does not have coproducts
- is not infinitary codistributive
- is not countably codistributive
- is not codistributive
- does not have exact cofiltered limits
- does not have cocartesian cofiltered limits
- does not have cofiltered-limit-stable epimorphisms
- does not satisfy CSP
- is not infinitary coextensive
- is not ℵ₁-cofiltered
- does not have cosifted limits
- is not conormal
- does not have countable coproducts
- does not have ℵ₂-small copowers
- is not quotient-trivial
- is not cototal
- is not Malcev
- does not have a parametrized natural numbers object
- is not complete
- is not locally poly-presentable
- is not cartesian closed
- does not have disjoint coproducts
- is not infinitary distributive
- is not countably distributive
- does not have exact filtered colimits
- does not have cartesian filtered colimits
- is not countably extensive
- does not have a terminal object
- does not have ℵ₂-small products
- does not have pullbacks
- does not have coequalizers of kernel pairs
- is not regular
- does not have a subobject classifier
- does not have a regular subobject classifier
- is not an elementary topos
- is not a Grothendieck topos
- is not a pretopos
- is not a quasitopos
- is not co-Malcev
- is not locally finitely copresentable
- is not essentially finite
- is not locally finitely multi-copresentable
- is not a dual generalized variety
- does not have disjoint finite products
- is not coextensive
- does not have ℵ₂-small coproducts
- is not coregular
- does not have a quotient object classifier
- does not have a regular quotient object classifier
- is not a Grothendieck cotopos
- does not have a natural numbers object
- is not locally cartesian closed
- does not have pullback-stable regular epimorphisms
- is not Barr-exact
- is not locally ℵ₁-copresentable
- is not dually finitary algebraic
- is not dually multi-algebraic
- does not have a strict terminal object
- is not Barr-coexact
- is not a precotopos
- is not dually one-sorted finitary algebraic
*This also uses the deduced satisfied properties.
Unknown properties
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Special objects
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Special morphisms
- isomorphisms: bijective maps
- monomorphisms: bijective maps
- epimorphisms: every morphism
- regular monomorphisms: same as isomorphisms
- regular epimorphisms: same as epimorphisms