QUANTUM AFFINE SYMMETRY IN VERTEX MODELS

We study the higher spin analogs of the six-vertex model on the basis of its symmetry under the quantum affine algebra U(q)(sl2). Using the method developed recently for the XXZ spin chain, we formulate the space of states, transfer matrix, vacuum, creation/annihilation operators of particles, and local operators, purely in the language of representation theory. We find that, regardless of the level of the representation involved, the particles have spin 1/2, and that the n-particle space has an RSOS type structure rather than a simple tensor product of the one-particle space. This agrees with the picture proposed earlier by Reshetikhin.