QUASI-GALOIS SYMMETRIES OF THE MODULAR S-MATRIX

The recently introduced Galois symmetries of rational conformal field theory are generalized, for the case of WZW theories, to ''quasi-Galoi s symmetries.'' These symmetries can be used to derive a large number of equalities and sum rules for entries of the modular matrix S, inclu ding some that previously had been observed empirically. In addition, quasi-Galois symmetries allow us to construct modular invariants and t o relate S-matrices as well as modular invariants at different levels. They also lead us to a convenient closed expression for the branching rules of the conformal embeddings g hooked right arrow <(so)over cap> (dim (g) over bar).