most recent 30 from http://mathoverflow.net 2013-05-25T14:41:45Z http://mathoverflow.net/feeds/question/2974 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/2974/a-theory-of-generalized-donaldson-thomas-invariants-by-joyce-song David Steinberg 2009-10-28T01:25:52Z 2009-11-09T00:12:12Z

<p>Is anyone else working through this paper : <a href="http://arxiv.org/abs/0810.5645" rel="nofollow">http://arxiv.org/abs/0810.5645</a> ? I am trying to verifying example 6.2 (m=2 for simplicity) using only the definitions, namely:</p> <p>J^{2\alpha}(\tau) = -1/4</p> <p>(where \alpha satisfies M^{\alpha}_ss = M^{\alpha}_st and that Ext^1(E, E)=0 for any E \in M^{\alpha}_ss and finally that the only object of M^{m\alpha}_ss is E ^{\oplus m})</p> <p>I keep getting -3/4. Has anyone else attempted to make such a computation? Did you get the answer you are supposed to get?</p>