| A primitive Mukai vector v=(r,H,s) with 2rs=H^2 defines the moduli Y of sheaves on a K3 surface X where Y is again a K3 surface. Divisorial conditions on moduli of X which imply that Y\cong X were studied in series of papers alg-geom/0206158, 0304415 (Carlo Madonna, Nikulin), 0307355, 0309348 (Nikulin). But, for a general Mukai vector v (alg-geom/0309348) the results were very complicated and unsatisfactory. Recently (see second variant of alg-geom/0309348) I significantly simplified these results and obtained satisfactory (?) results in general. |