What is an antiequivalence of two categories? - MathOverflow most recent 30 from http://mathoverflow.net 2013-05-22T09:43:47Z http://mathoverflow.net/feeds/question/21744 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/21744/what-is-an-antiequivalence-of-two-categories What is an antiequivalence of two categories? Yujia Qiu 2010-04-18T14:05:16Z 2010-04-18T23:11:18Z <p>Hello everyone, I am a newbie to the category theory. While reading some paper about infinite Galois theory, the 'anti-equivalence' of two categories showed up. Could anyone give me a 'good' explanation what this means? Thanks a lot.</p> http://mathoverflow.net/questions/21744/what-is-an-antiequivalence-of-two-categories/21746#21746 Answer by Robin Chapman for What is an antiequivalence of two categories? Robin Chapman 2010-04-18T14:11:10Z 2010-04-18T14:11:10Z <p>All it means that one of the categories is equivalent to the opposite of the other.</p> <p>Wikipedia has informative pages on opposites of categories and equivalences of categories:</p> <p><a href="http://en.wikipedia.org/wiki/Opposite_%28category_theory%29" rel="nofollow">http://en.wikipedia.org/wiki/Opposite_%28category_theory%29</a> ,</p> <p><a href="http://en.wikipedia.org/wiki/Equivalence_of_categories" rel="nofollow">http://en.wikipedia.org/wiki/Equivalence_of_categories</a> .</p>