N-category

N-category

In mathematics, n-categories are a high-order generalization of the notion of category. The category of (small) "n"-categories "n"-Cat is defined by induction on "n" by:
* the category 0-Cat is the category Set of sets and functions,
* the category ("n"+1)-Cat is the category of categories enriched over the category "n"-Cat.

The monoidal structure of Set is the one given by the cartesian product as tensor and a singleton as unit. In fact any category with finite products can be given a monoidal structure. The recursive construction of n-Cat works fine because if a category C has finite products, the category of C-enriched categories has finite products too.

In particular, the category 1-Cat is the category Cat of small categories and functors.

N-categories have given rise to the higher category theory where several types of n-categories are studied. The necessity to weaken the definition of a n-category for homotopic purposes has led to the definition of weak n-categories. For distinction, the n-categories as defined above are called strict.

See also

* 2-category
* Weak n-category
* n-category number

References

*cite book
author = Tom Leinster
year = 2004
title = Higher Operads, Higher Categories
publisher = Cambridge University Press
url = http://www.maths.gla.ac.uk/~tl/book.html

*cite book
author = Eugenia Cheng, Aaron Lauda
year = 2004
title = Higher-Dimensional Categories: an illustrated guide book
url = http://www.math.uchicago.edu/~eugenia/guidebook/guidebook-new.pdf


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Category management — is a retailing concept in which the total range of products sold by a retailer is broken down into discrete groups of similar or related products; these groups are known as product categories. Examples of grocery categories may be : tinned fish,… …   Wikipedia

  • Category utility — is a measure of category goodness defined in Harvtxt|Gluck|Corter|1985 and Harvtxt|Corter|Gluck|1992. It was intended to supersede more limited measures of category goodness such as cue validity (Harvnb|Reed|1972;Harvnb|Rosch|Mervis|1975) and… …   Wikipedia

  • Category — may refer to: *Category (philosophy) *taxonomic category Taxonomic rank *Category (grammar) *Category (mathematics) * Categories (Aristotle) *Category (Kant) *Categories (Stoic) *Categories (game), a game involving naming categories of things… …   Wikipedia

  • Category 6 cable — Category 6 cable, commonly referred to as Cat 6, is a cable standard for Gigabit Ethernet and other network protocols that is backward compatible with the Category 5/5e and Category 3 cable standards. Cat 6 features more stringent specifications… …   Wikipedia

  • Category 5 — may refer to: * Category 5 (album), an album from rock band, FireHouse *Category 5 cable, used for carrying data *Category 5 computer virus, as classified by Symantec Corporation *Category 5 Records, a record label *Category 5 Tropical Cyclone,… …   Wikipedia

  • Category — • The term was transferred by Aristotle from its forensic meaning (procedure in legal accusation) to its logical use as attribution of a subject Catholic Encyclopedia. Kevin Knight. 2006. Category     Category …   Catholic encyclopedia

  • Category 5 cable — Category 5 cable, commonly known as Cat 5, is a twisted pair cable type designed for high signal integrity. Many such cables are unshielded but some are shielded. Category 5 has been superseded by the Category 5e specification. This type of cable …   Wikipedia

  • Category 3 cable — Category 3 cable, commonly known as Cat 3, is an unshielded twisted pair (UTP) cable designed to reliably carry data up to 10 Mbit/s, with a possible bandwidth of 16 MHz. It is part of a family of copper cabling standards defined jointly by the… …   Wikipedia

  • Category 3 — can refer to: *Category 3 cable, a specification for data cabling *British firework classification *Category 3 Tropical Cyclone on the Saffir Simpson Hurricane Scale. *Category 3 Pandemic on the Pandemic Severity Index *Category III, a rating in… …   Wikipedia

  • Category 4 — can refer to:*Category 4 Tropical Cyclone on the Saffir Simpson Hurricane Scale. *Category 4 Pandemic on the Pandemic Severity Index *Category 4 cable *The upper category for professional fireworks in England …   Wikipedia

  • category killer — cat‧e‧go‧ry kil‧ler [ˈkætgri ˌkɪlə ǁ gɔːri ˌkɪlər] noun [countable] MARKETING a very big specialized international chain store that causes local competitors to go out of business: • Category killers focus on one area of product, offering wider… …   Financial and business terms

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”