ALGEBRAIC BETHE-ANSATZ WITH BOUNDARY-CONDITION FOR SUP,Q(2) INVARIANT SPIN CHAIN

We have analysed a generalized Heisenberg spin chain invariant under the quantum group SU(p,q)(2). Instead of the usual periodic boundary condition, non-trivial boundary conditions are imposed a la Sklyanin. R-matrix and Bethe eigenstates are constructed explicitly. The R-matrix describes a vertex type model which can be shown to be connected to the xxz type six vertex model under the Akutsu-Deguchi-Wadati-type symmetry-breaking transformation.