With braiding
With duals for objects
category with duals (list of them)
dualizable object (what they have)
ribbon category, a.k.a. tortile category
With duals for morphisms
With traces
Closed structure
Special sorts of products
Semisimplicity
Morphisms
Internal monoids
Examples
Theorems
In higher category theory
A category with duals is a category where objects and/or morphisms have duals. This exists in several flavours; this list is mostly taken from a recent categories
list post from Peter Selinger.
A left autonomous category is a monoidal category in which every object is dualisable on the left.
A right autonomous category is a monoidal category in which every object is dualisable on the right.
An autonomous category, or rigid category is a monoidal category that is both left and right autonomous. Note that any braided monoidal category is autonomous on both sides if it is autonomous on either side.
A pivotal category is an autonomous category equipped with a monoidal natural isomorphism from the identity functor to the double dual functor. A one-sided autonomous category with such an isomorphism is automatically two-sided autonomous. Although each braided autonomous category has an isomorphism from to , such a category is not necessarily pivotal because this isomorphism is not in general monoidal. On the other hand, every balanced autonomous category is pivotal.
A spherical category is a pivotal category where the left and right trace operations coincide on all objects.
A tortile category, or ribbon category, is a balanced autonomous (therefore pivotal) category in which the twist on is the dual of the twist on .
A compact closed category is a symmetric tortile category, or equivalently, a symmetric autonomous category.
The -autonomous categories do not really belong on this list; being -autonomous is logically independent of being autonomous, and while -autonomous categories have duals, these are not in general duals in the sense of a dualisable object. However, any compact closed category is -autonomous.
Likewise, closed categories or closed monoidal categories do not really belong on this list, but there is a sense of dual there which should be carefully distinguished from the primary sense here, which is generally stronger. See dual object in a closed category.
One might write something about these too, or put them on a separate page. In the meantime, see the table of contents to the right.
There at least two commonspread kinds of categories with duals for morphisms:
Moreover, every category enriched in one of the kind of categories listed above will have a notion of ‘dual’ for its morphisms.
categories
post of 2010-05-15;Last revised on October 21, 2021 at 09:19:05. See the history of this page for a list of all contributions to it.