CURRENT-ALGEBRA REALIZATION OF R-MATRICES ASSOCIATED TO Z2-GRADED LIE-ALGEBRAS

The two-pole constant parametric non skew-symmetric classical R-matrices constructed from any symmetric space G/H for G semi-simple, and their q-poles generalizations, are realized as the Poisson bracket structure of a Lax operator L(x, lambda). This operator is obtained from a centrally extended twisted current algebra of fields reduced by the dual of the Cartan involution defining the canonical decomposition of the Lie algebra of G associated with the symmetric space considered. This is an extension of the Faddeev-Reshetikhin mean procedure to the case when a cyclic group acts on the spectral parameter.