We count the number of bound states of BPS black holes on local Calabi-Yau threefolds involving a Riemann surface of genus g. We show that the corresponding gauge theory on the brane reduces to a q-deformed Yang-Mills theory on the Riemann surface. Following the recent connection between the black hole entropy and the topological string partition function, we find that for a large black hole charge N , up to corrections of O(e ), ZBH is given as a sum of a square of chiral blocks, each of which… CONTINUE READING