New integrable canonical structures in two-dimensional models

We develop a new canonical r-s matrix type approach for integrable two-dimensional models of non-ultralocal type. The L-matrices algebra and the monodromy matrices' algebras are given in terms of the usual r-matrix and of the new s-matrix, which, for consistency (Jacobi identity) have to obey an extended, dynamical Yang-Baxter type equation. The possible violation of the Jacobi identity arising in the (naive) equal-point limit of the monodromy matrices' algebras is discussed and a general, consistent procedure, i.e. satisfying the Jacobi identity, is defined. The method is applied to the complex sine-Gordon model. (orig.)