most recent 30 from http://mathoverflow.net 2013-06-19T12:27:44Z http://mathoverflow.net/feeds/question/22514 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/22514/sign-gordon-equation Kaveh Khodjasteh 2010-04-25T16:08:08Z 2010-04-26T11:56:19Z

<p>What can be said and done about the "SIGN-Gordon equation"? $$\varphi_{tt}- \varphi_{xx} + \text{sgn}(\varphi) = 0.$$ It came up <a href="http://mathoverflow.net/questions/22281/can-i-relate-the-l1-norm-of-a-function-to-its-fourier-expansion/" rel="nofollow">here</a>.</p>

http://mathoverflow.net/questions/22514/sign-gordon-equation/22590#22590 Gjergji Zaimi 2010-04-26T11:56:19Z 2010-04-26T11:56:19Z

<p>Turns out it appears in literature as the "signum-Gordon equation". For example the paper <a href="http://th-www.if.uj.edu.pl/acta/vol38/pdf/v38p3099.pdf" rel="nofollow">Signum-Gordon wave equation and its self-similar solutions</a></p>