Fields and Symmetries of 2D Strings

Abstract

We describe some recent progress in understanding and formulating string theory which is based on extensive studies of strings in lower (D=2) dimension. At the center is a large $W_{\infty }$ symmetry that appears most simply in the matrix model picture. In turn the symmetry defines the dynamics giving Ward identities and the complete S-matrix. The integrability aspect where nonlinear string phenomena emerges from linear matrix model dynamics is emphasized. Extensions involving couplings of discrete topological fields to the tachyon are also described.

13 pages, phyzzx