J. Algebraic Geom. 7 (1998), no. 1, 183–193. Richard E. Borcherds † Mathematics department, Evans Hall, 3840, UC Berkeley, CA 94720-3840 D.P.M.M.S., 16 Mill Lane, Cambridge CB2 1SB, UK email: [email protected] Ludmil Katzarkov M.S.R.I., 1000 Centennial Drive, Berkeley, CA 94720 Department of Mathematics, UC Irvine, Irvine, CA 92697-3875 email: [email protected] Tony Pantev ‡ Department of ...