most recent 30 from http://mathoverflow.net 2013-05-23T23:19:26Z http://mathoverflow.net/feeds/user/22342 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/63902/regular-tm-is-undecidable/91966#91966 unknown (google) 2012-03-23T01:15:27Z 2012-03-23T01:15:27Z

<p>I think we should think this way. If M2 is a machine that accepts regular languages, it must accept some string other than 0n1n, which means M must accpet w.</p> <p>If M does not accept w, M2 will not accept any regular string, thus L(M2) is irregular.</p>