2-DIMENSIONAL BLACK-HOLE AS A TOPOLOGICAL COSET MODEL OF C=1 STRING THEORY

We show that a special superconformal coset (with c = 3) is equivalent to c = 1 matter coupled to two-dimensional gravity. This identificati on allows a direct computation of the correlation functions of the c = 1 non-critical string to all genus, and at nonzero cosmological const ant, directly from the continuum approach. The results agree with thos e of the matrix model. Moreover we connect our coset with a twisted ve rsion of a euclidean two-dimensional black hole, in which the ghost an d matter systems are mixed.