N=4 superconformal symmetry for the covariant quantum superstring

We extend our formulation of the covariant quantum superstring as a WZNW model with N=2 superconformal symmetry to N=4. The two anticommuting BRST charges in the N=4 multiplet of charges are the usual BRST charge QS and a charge QV proposed by Dijkgraaf, Verlinde and Verlinde for topological models. Using our recent work on “gauging cosets”, we then construct a further charge QC which anticommutes with QC+QV and which is intended for the definition of the physical spectrum.