The BRST Operator for the Large $N=4$ Superconformal Algebra

Fiorenzo Bastianelli, Nobuyoshi Ohta

Published 1994-02-21, updated 1994-06-27Version 2

We review the detailed structure of the large $N=4$ superconformal algebra, and construct its BRST operator which constitutes the main object for analyzing $N=4$ strings. We then derive the general condition for the nilpotency of the BRST operator and show that there exists a line of critical $N=4$ string theories.