sequential colimits
A category has sequential colimits if it has colimits of diagrams of the following form:
- Dual property: sequential limits
- Related properties: filtered colimits
- nLab Link
Relevant implications
coequalizers and countable coproducts implies sequential colimits
[dualized] Mac Lane, V.2, Prop. 3. The proof can easily be adapted to this case. Namely, the limit of is the equalizer of two suitable endomorphisms of .finite coproducts and sequential colimits implies countable coproducts
[dualized] If is an infinite sequence of objects, then their product is the limit of the sequence .filtered colimits implies sequential colimits
[dualized] trivialself-dual and sequential limits implies sequential colimits
trivial by self-dualityself-dual and sequential colimits implies sequential limits
trivial by self-duality
Examples
- category of abelian groups
- category of Banach spaces with linear contractions
- category of commutative rings
- category of fields
- category of finite sets and bijections
- category of finite sets and surjections
- category of groups
- category of left R-modules
- category of locally ringed spaces
- category of M-sets
- category of measurable spaces
- category of metric spaces with ∞ allowed
- category of metric spaces with non-expansive maps
- category of monoids
- category of non-empty sets
- category of pointed sets
- category of posets
- category of rings
- category of rngs
- category of sets
- category of simplicial sets
- category of small categories
- category of topological spaces
- category of vector spaces
- category of Z-functors
- delooping of a non-trivial finite group
- delooping of an infinite group
- discrete category on two objects
- empty category
- partial order [0,1]
- partial order of extended natural numbers
- partial order of ordinal numbers
- preorder of integers w.r.t. divisiblity
- trivial category
- walking isomorphism
- walking morphism
- walking parallel pair of morphisms
Counterexamples
- category of combinatorial species
- category of finite abelian groups
- category of finite orders
- category of finite sets
- category of finite sets and injections
- category of finitely generated abelian groups
- delooping of the additive monoid of natural numbers
- partial order of natural numbers
Unknown
For these categories the database has no info if they satisfy this property or not.