most recent 30 from http://mathoverflow.net 2013-05-23T20:24:15Z http://mathoverflow.net/feeds/question/57516 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/57516/period-of-the-identity-element rakaka 2011-03-05T23:58:48Z 2011-03-05T23:58:48Z

<p>I am reading about the cyclic group of order 4, and it says that the group contains two operation of period 4. I don't understand why, it is because the identity element is also of period 4? or because the generators can be a clockwise and counterclockwise quarter-turns?</p>