Matrix model from N=2 orbifold partition function

The orbifold generalization of the partition function, which would describe the gauge theory on the ALE space, is investigated from the combinatorial perspective. It is shown that the root of unity limit q -> exp(2 pi i/k) of the q-deformed partition function plays a crucial role in the orbifold projection while the limit q -> 1 applies to R-4. Then starting from the combinatorial representation of the partition function, a new type of multi-matrix model is derived by considering its asymptotic behavior. It is also shown that Seiberg-Witten curve for the corresponding gauge theory arises from the spectral curve of this multi-matrix model.