Sigma model approach to string theory

Abstract

A review of the $\ddot{I}ƒ$-model approach to derivation of effective string equations of motion for the massless fields is presented. We limit our consideration to the case of the tree approximation in the closed bosonic string theory.

54 pages. Based on lectures at Superstrings '88, ICTP Trieste Spring School, 11-19 April 1988