A note on the Zakharov-Shabat topological model

In this note I discuss some features of the topological theory obtained from the Zakharov-Shabat (or general sl(2,C)) hierarchy, and comment on some possible physical and/or mathematical interpretations of it.Comment: 9 page

String Theory and the CPT Theorem on the World-Sheet

We study the CPT theorem for a two-dimensional conformal field theory on an arbitrary Riemann surface. On the sphere the theorem follows from the assumption that the correlation functions have standard hermiticity properties and are invariant under the transformation $z \rightarrow 1/z$. The theorem can then be extended to higher genus surfaces by sewing. We show that, as a consequence of the CPT theorem on the world-sheet, the scattering $T$-matrix in string theory is {\sl formally\/} hermitean at any loop order.Comment: TeX macros include

Thermodynamics of Two-Dimensional Black-Holes

We explore the thermodynamics of a general class of two dimensional dilatonic black-holes. A simple prescription is given that allows us to compute the mass, entropy and thermodynamic potentials, with results in agreement with those obtained by other methods, when available.Comment: 12 page

Bosonization of World-Sheet Fermions in Minkowski Space-Time

We propose a way of bosonizing free world-sheet fermions for $4$-dimensional heterotic string theory formulated in Minkowski space-time. We discuss the differences as compared to the standard bosonization performed in Euclidean space-time.Comment: 1+9 pages, TeX macros include