THE ALGEBRA OF NONLOCAL CHARGES IN NONLINEAR SIGMA-MODELS

We obtain the exact classical algebra obeyed by the conserved non-loca l charges in bosonic non-linear sigma models. Part of the computation is specialized for a symmetry group O(N). As it turns out the algebra corresponds to a cubic deformation of the Kac-Moody algebra. We genera lize the results for the presence of a Wess-Zumino term. The algebra i s very similar to the previous one, now containing a calculable correc tion of order one unit lower. The relation with Yangians and the role of the results in the context of Lie-Poisson algebras are also discuss ed.