CatDat

self-dual

A category is self-dual if it is equivalent to its opposite (or dual) category.

• Dual property: self-dual (self-dual)
• nLab Link

Relevant implications

• accessible andself-dual implies coaccessible
• Barr-coexact andself-dual implies Barr-exact
• Barr-exact andself-dual implies Barr-coexact
• binary copowers andself-dual implies binary powers
• binary coproducts andself-dual implies binary products
• binary powers andself-dual implies binary copowers
• binary products andself-dual implies binary coproducts
• cartesian closed andself-dual implies cocartesian coclosed
• cartesian filtered colimits andself-dual implies cocartesian cofiltered limits
• CIP andself-dual implies CSP
• co-Malcev andself-dual implies Malcev
• coaccessible andself-dual implies accessible
• cocartesian coclosed andself-dual implies cartesian closed
• cocartesian cofiltered limits andself-dual implies cartesian filtered colimits
• cocomplete andself-dual implies complete
• codistributive andself-dual implies distributive
• coequalizers andself-dual implies equalizers
• coextensive andself-dual implies extensive
• cofiltered limits andself-dual implies filtered colimits
• cofiltered andself-dual implies filtered
• cofiltered-limit-stable epimorphisms andself-dual implies filtered-colimit-stable monomorphisms
• cogenerating set andself-dual implies generating set
• cogenerator andself-dual implies generator
• cokernels andself-dual implies kernels
• complete andself-dual implies cocomplete
• connected colimits andself-dual implies connected limits
• connected limits andself-dual implies connected colimits
• conormal andself-dual implies normal
• copowers andself-dual implies powers
• coproducts andself-dual implies products
• coquotients of cocongruences andself-dual implies quotients of congruences
• coreflexive equalizers andself-dual implies reflexive coequalizers
• coregular andself-dual implies regular
• cosifted limits andself-dual implies sifted colimits
• cosifted andself-dual implies sifted
• counital andself-dual implies unital
• countable copowers andself-dual implies countable powers
• countable coproducts andself-dual implies countable products
• countable powers andself-dual implies countable copowers
• countable products andself-dual implies countable coproducts
• countably codistributive andself-dual implies countably distributive
• countably distributive andself-dual implies countably codistributive
• CSP andself-dual implies CIP
• directed colimits andself-dual implies directed limits
• directed limits andself-dual implies directed colimits
• disjoint coproducts andself-dual implies disjoint products
• disjoint finite coproducts andself-dual implies disjoint finite products
• disjoint finite products andself-dual implies disjoint finite coproducts
• disjoint products andself-dual implies disjoint coproducts
• distributive andself-dual implies codistributive
• effective cocongruences andself-dual implies effective congruences
• effective congruences andself-dual implies effective cocongruences
• epi-regular andself-dual implies mono-regular
• equalizers andself-dual implies coequalizers
• exact cofiltered limits andself-dual implies exact filtered colimits
• exact filtered colimits andself-dual implies exact cofiltered limits
• extensive andself-dual implies coextensive
• filtered colimits andself-dual implies cofiltered limits
• filtered andself-dual implies cofiltered
• filtered-colimit-stable monomorphisms andself-dual implies cofiltered-limit-stable epimorphisms
• finite copowers andself-dual implies finite powers
• finite coproducts andself-dual implies finite products
• finite powers andself-dual implies finite copowers
• finite products andself-dual implies finite coproducts
• finitely cocomplete andself-dual implies finitely complete
• finitely complete andself-dual implies finitely cocomplete
• generating set andself-dual implies cogenerating set
• generator andself-dual implies cogenerator
• Grothendieck abelian andself-dual implies trivial
• groupoid implies self-dual
• groupoid implies self-dual
• infinitary codistributive andself-dual implies infinitary distributive
• infinitary coextensive andself-dual implies infinitary extensive
• infinitary distributive andself-dual implies infinitary codistributive
• infinitary extensive andself-dual implies infinitary coextensive
• initial object andself-dual implies terminal object
• kernels andself-dual implies cokernels
• left cancellative andself-dual implies right cancellative
• locally cartesian closed andself-dual implies locally cocartesian coclosed
• locally cocartesian coclosed andself-dual implies locally cartesian closed
• locally copresentable andself-dual implies locally presentable
• locally presentable andself-dual implies locally copresentable
• Malcev andself-dual implies co-Malcev
• mono-regular andself-dual implies epi-regular
• multi-cocomplete andself-dual implies multi-complete
• multi-complete andself-dual implies multi-cocomplete
• multi-initial object andself-dual implies multi-terminal object
• multi-terminal object andself-dual implies multi-initial object
• normal andself-dual implies conormal
• powers andself-dual implies copowers
• products andself-dual implies coproducts
• pullbacks andself-dual implies pushouts
• pushouts andself-dual implies pullbacks
• quotient object classifier andself-dual implies subobject classifier
• quotient-trivial andself-dual implies subobject-trivial
• quotients of congruences andself-dual implies coquotients of cocongruences
• reflexive coequalizers andself-dual implies coreflexive equalizers
• regular quotient object classifier andself-dual implies regular subobject classifier
• regular subobject classifier andself-dual implies regular quotient object classifier
• regular andself-dual implies coregular
• right cancellative andself-dual implies left cancellative
• self-dual andsequential colimits implies sequential limits
• self-dual andsequential limits implies sequential colimits
• self-dual andsifted colimits implies cosifted limits
• self-dual andsifted implies cosifted
• self-dual andstrict initial object implies strict terminal object
• self-dual andstrict terminal object implies strict initial object
• self-dual andsubobject classifier implies quotient object classifier
• self-dual andsubobject-trivial implies quotient-trivial
• self-dual andterminal object implies initial object
• self-dual andunital implies counital
• self-dual andwell-copowered implies well-powered
• self-dual andwell-powered implies well-copowered
• self-dual andwide pullbacks implies wide pushouts
• self-dual andwide pushouts implies wide pullbacks
• trivial implies self-dual

Examples

There are 17 categories with this property.

• category of finite abelian groups
• category of finite sets and bijections
• category of sets and relations
• delooping of a non-trivial finite group
• delooping of an infinite countable group
• delooping of the additive monoid of natural numbers
• discrete category on two objects
• empty category
• poset [0,1]
• trivial category
• walking commutative square
• walking composable pair
• walking idempotent
• walking isomorphism
• walking morphism
• walking parallel pair
• walking splitting

Counterexamples

There are 63 categories without this property.

• category of abelian groups
• category of abelian sheaves
• category of algebras
• category of Banach spaces with linear contractions
• category of combinatorial species
• category of commutative algebras
• category of commutative monoids
• category of commutative rings
• category of compact Hausdorff spaces
• category of countable groups
• category of countable sets
• category of fields
• category of finite groups
• category of finite ordered sets
• category of finite sets
• category of finite sets and injections
• category of finite sets and surjections
• category of finitely generated abelian groups
• category of free abelian groups
• category of groups
• category of Hausdorff spaces
• category of Jónsson-Tarski algebras
• category of left modules over a division ring
• category of left modules over a ring
• category of locally ringed spaces
• category of M-sets
• category of measurable spaces
• category of metric spaces with continuous maps
• category of metric spaces with non-expansive maps
• category of metric spaces with ∞ allowed
• category of monoids
• category of non-empty sets
• category of pairs of sets
• category of pointed sets
• category of pointed topological spaces
• category of posets
• category of prosets
• category of pseudo-metric spaces with non-expansive maps
• category of rings
• category of rngs
• category of schemes
• category of semigroups
• category of sets
• category of sets with finite-to-one maps
• category of sheaves
• category of simplicial sets
• category of small categories
• category of smooth manifolds
• category of topological spaces
• category of torsion abelian groups
• category of torsion-free abelian groups
• category of vector spaces
• category of Z-functors
• delooping of the additive monoid of ordinal numbers
• dual of the category of sets
• poset of extended natural numbers
• poset of natural numbers
• poset of ordinal numbers
• proset of integers w.r.t. divisibility
• simplex category
• walking coreflexive pair
• walking fork
• walking span

Unknown

There are 0 categories for which the database has no information on whether they satisfy this property.

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