Difference between revisions of "Category (category theory)"
(New page: A category, <math>\mathcal{C}</math>, is a mathematical object consisting of: * A class, <math>\text{Ob}(\mathcal{C})</math> of objects. * For every pair of objects <math>A,B\in \text...) |
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Revision as of 01:06, 2 September 2008
A category, , is a mathematical object consisting of:
- A class, of objects.
- For every pair of objects , a class of morphisms from to . (We sometimes write to mean .)
- For every three objects, , a binary operation called composition, which satisfies:
- (associativity) Given , and we have
- (identity) For and object , there is an identity morphism such that for any :