  This review gives results on vertex operators for the Type IIB superstring in
an AdS3 x S3 background with Ramond-Ramond flux, which were presented at
Strings 2000. Constraint equations for these vertex operators are derived, and
their components are shown to satisfy the supergravity linearized equations of
motion for the six-dimensional (2,0) theory of a supergravity and tensor
multiplet expanded around AdS3 x S3 spacetime.
