A NOTE ON (0,2) MODELS ON CALABI-YAU COMPLETE-INTERSECTIONS

In the class of (0, 2) heterotic compactifications, which has been con structed in the framework of gauged linear sigma models, the Calabi-Ya u varieties X are realized as complete intersections of hypersurfaces in toric varieties P-Sigma and the corresponding gauge bundles (or mor e generally gauge sheaves) epsilon are defined by some short exact seq uences. We show that there is yet another degree of freedom in reservi ng singularities in such models which is related to the possible choic es of nef partitions of the anticanonical divisors in Gorenstein-Fano toric varieties P-Sigma. (C) 1998 Elsevier Science B.V.