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category

File:Category_SVG.svg · Wikimedia Commons · See Wikimedia Commons

EntityQ719395· pop 38· linked from 984 articles

algebraic structure of objects and morphisms between objects, which can be associatively composed if the (co)domains agree

Wikidata facts

Has part
morphism
Follows
class
Image
Category SVG.svg
Show 8 more facts
discoverer or inventor
Saunders Mac Lane
time of discovery or invention
1945-00-00
different from
Category
studied by
category theory
series ordinal
1
on focus list of Wikimedia project
Wikipedia:Vital articles/Level/4
maintained by WikiProject
WikiProject Mathematics
quantity symbol (string)
C
Sources (3)

via Wikidata · CC0

~21 min read

Encyclopedic overview

This is a category with a collection of objects A, B, C and collection of morphisms denoted f, g, g ∘ f, and the loops are the identity arrows. This category is typically denoted by a boldface 3.

In mathematics, a category (sometimes called an abstract category to distinguish it from a concrete category) is a collection of "objects" that are linked by "arrows". A category has two basic properties: the ability to compose the arrows associatively and the existence of an identity arrow for each object. A simple example is the category of sets, whose objects are sets and whose arrows are functions.

Excerpted from Wikipedia’s “category” article, available under the CC BY-SA 4.0 licence.

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