We introuduce a unified method which can be applied to any WZW model at
arbitrary level to search systematically for modular invariant physical
partition functions. Our method is based essentially on modding out a known
theory on group manifold G by a discrete group Ξ.
We apply our method to su(n)β with n=2,3,4,5,6, and to
g2ββ models, and obtain all the known partition functions and some
new ones, and give explicit expressions for all of them.Comment: 30 page ,SUTDP/11/93/72 Department of Physics, Sharif University of
Technolog