THE N-MATRIX MODEL AND GAUGED WZW MODELS

It has been shown that the N matrix model of two-dimensional gravity is related to certain topological field theories obtained by twisting the N = 2 minimal models. In this paper, the latter theories are studied by realizing them as gauged WZW models. This leads to an algebrogeometric description of the topological correlation functions from which many of their standard properties can be recovered. We find that in a certain sense the model at level k, with k analytically continued to -3, is equivalent to the Penner model (which computes the Euler characteristic of the moduli space of Riemann surfaces). We also gain better understanding of formulas of Lerche, Vafa, and Warner; Gepner; and Spiegelglas.