Implication Details
Assumptions: wide pullbacks
Conclusions: cofiltered limits, pullbacks
This is an equivalence.
Reason: To prove , a wide pullback can be constructed as a cofiltered limit of finite pullbacks, and finite pullbacks can be reduced to binary pullbacks (the empty-indexed pullback always exists). Conversely, assume that wide pullbacks exist in . For every object then the slice category has wide pullbacks and a terminal object, hence is complete. Since a cofiltered limit can be finally reduced to such a slice, we are done.
Show 63 categories using this implication
- empty category
- trivial category
- discrete category on two objects
- category of abelian groups
- category of algebras
- category of finite sets and bijections
- delooping of an infinite countable group
- delooping of the additive monoid of natural numbers
- delooping of the additive monoid of ordinal numbers
- category of commutative algebras
- category of commutative monoids
- category of commutative rings
- category of small categories
- category of finite sets and injections
- category of finite sets and surjections
- category of finite ordered sets
- category of finite sets
- category of fields
- category of free abelian groups
- category of groups
- category of Hausdorff spaces
- category of Jónsson-Tarski algebras
- category of locally ringed spaces
- category of M-sets
- category of smooth manifolds
- category of measurable spaces
- category of metric spaces with non-expansive maps
- category of metric spaces with continuous maps
- category of metric spaces with ∞ allowed
- category of monoids
- poset of natural numbers
- poset of extended natural numbers
- poset of ordinal numbers
- category of pseudo-metric spaces with non-expansive maps
- category of posets
- category of prosets
- category of left modules over a ring
- category of left modules over a division ring
- category of rings
- category of rngs
- category of schemes
- category of sets
- category of countable sets
- category of sets with finite-to-one maps
- category of pairs of sets
- category of sheaves
- category of abelian sheaves
- category of combinatorial species
- category of topological spaces
- category of pointed topological spaces
- category of torsion abelian groups
- category of torsion-free abelian groups
- category of vector spaces
- category of Z-functors
- proset of integers w.r.t. divisibility
- poset [0,1]
- category of simplicial sets
- walking commutative square
- walking coreflexive pair
- walking idempotent
- walking isomorphism
- walking parallel pair
- walking span