A theory of generalized Donaldson-Thomas invariants. II. Multiplicative identities for Behrend functions

This paper has been withdrawn, not because of any errors (that we know of), but because rather than presenting our material as a series of 3 papers, as we originally intended, we have now combined them into one long paper, which is “A theory of generalized Donaldson-Thomas invariants”, arXiv:0810.5645v3, June 2009, 181 pages, and this paper has been incorporated into that.