COVARIANTLY COUPLED CHIRAL ALGEBRAS

New extended conformal algebras are constructed by conformal reductions of sl(N) WZWN models. These are associated with the inequivalent sl2 embeddings into sl(N). Among other things, the conformal weights of the generators and the occurrence of Kac-Moody and W(n) subalgebras are determined by the branching rules of the adjoint representation for the particular embedding. For some representative classes the algebras are constructed explicitly. In general they are coupled chiral algebras suggesting that they correspond to the symmetries of certain interacting conformal field theories. Moreover we find that a (minimal) covariant coupling is present which is related to a generalized Gelfand-Dickii structure. Some aspects of the quantization are addressed, in particular the c-values are determined. We introduce a new hybrid realization of KM algebras which interpolates between a realization of currents and of free fields, in which the constraints can be imposed in a very natural way.