A Derivation of the BRST Operator for Non-Critical W-Strings

E. Bergshoeff, A. Sevrin, X. Shen

Published 1992-09-11Version 1

We derive the recently proposed BRST charge for non-critical W strings from a Lagragian approach. The basic observation is that, despite appearances, the combination of two classical ``matter'' and ``Toda'' w_3 systems leads to a closed modified gauge algebra, which is of the so-called soft type. Based on these observations, a novel way to construct critical W_3 strings is given.