  We have previously described a way of describing the relation between
unintegrated and integrated vertex operators in AdS5xS5 which uses the
interpretation of the BRST cohomology as a Lie algebra cohomology and
integrability properties of the AdS background. Here we clarify some details of
that description, and develop a similar approach for an arbitrary curved
background with nondegenerate RR bispinor. For an arbitrary curved background,
the sigma-model is not integrable. However, we argue that a similar
construction still works using an infinite-dimensional Lie algebroid.
