User petrus - MathOverflow most recent 30 from http://mathoverflow.net 2013-05-24T01:04:00Z http://mathoverflow.net/feeds/user/11860 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/1890/describe-a-topic-in-one-sentence/65532#65532 Answer by Petrus for Describe a topic in one sentence. Petrus 2011-05-20T12:07:50Z 2011-05-20T14:50:45Z <p>I think this belongs on this list too:</p> <p>The <em>theory of groups</em> is a branch of mathematics in which one does something to something and then compares the results with the result of doing the same thing to something else, or something else to the same thing. – <a href="http://www.mathacademy.com/pr/quotes/index.asp?ACTION=TOP&amp;VAL=group%20theory" rel="nofollow">James Newman</a></p> http://mathoverflow.net/questions/64905/which-book-would-you-like-to-see-texified/64910#64910 Answer by Petrus for Which book would you like to see "texified"? Petrus 2011-05-13T17:48:23Z 2011-05-13T17:48:23Z <p>"Lectures on Chevalley Groups" - by Robert Steinberg</p> http://mathoverflow.net/questions/1890/describe-a-topic-in-one-sentence/65532#65532 Comment by Petrus Petrus 2011-05-20T14:48:38Z 2011-05-20T14:48:38Z @Todd Trimble If you study groups by their actions on sets, &quot;\$x^g\$&quot; is &quot;doing g to x&quot;. Natural questions are like &quot;when does \$x^g = x^h\$?&quot; i.e. when does doing something different on the same thing give the same result? http://mathoverflow.net/questions/64905/which-book-would-you-like-to-see-texified/64910#64910 Comment by Petrus Petrus 2011-05-16T08:10:23Z 2011-05-16T08:10:23Z @Emmanuel Kowalski: I would appreciate that as well, I've been looking forever by now.