The Ring Structure of Chiral Operators for Minimal Models Coupled to 2D   Gravity
  (Talk presented at the 1992 ICTP summer workshop in high energy physics and cosmology) The BRST cohomology ring for $(p,q)$ models coupled to gravity is discussed. In addition to the generators of the ghost number zero ring, the existence of a generator of ghost number $-1$ and its inverse is proven and used to construct the entire ring. Some comments are made regarding the algebra of the vector fields on the ring and the supersymmetric extension. 
M.H. Sarmadi