most recent 30 from http://mathoverflow.net 2013-05-19T17:25:05Z http://mathoverflow.net/feeds/user/12598 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/42512/awfully-sophisticated-proof-for-simple-facts/53672#53672 William Hale 2011-01-29T03:00:35Z 2011-01-29T03:00:35Z

<p>Using character theory, any group of order 4 is abelian since the only way to write 4 as a sum of squares is 4 = 1^2 + 1^2 + 1^2 + 1^2.</p>