YANGIAN SYMMETRY AND VIRASORO CHARACTER IN A LATTICE SPIN SYSTEM WITHLONG-RANGE INTERACTIONS

We consider the symmetry of lattice su(n) spin systems with inverse sq uare exchange; the Haldane-Shastry model and the Polychronakos-Frahm m odel, It is shown that both systems have yangian symmetry for a finite number of sites, Based on the yangian symmetry the energy spectrum is considered. Furthermore the representation for motifs and the relatio ns with the Virasoro character for su(n) level-1 Wess-Zumino-Witten th eory are discussed.