EVEN LINKAGE CLASSES

In this paper we generalize the epsilon and N-type resolutions used by Martin-Deschamps and Perrin for curses in P-3 to subschemes of pure c odimension in projective space,and shows that these resolutions are in terchanged Ly the mapping cone procedure under 3 simple linkage. Via t hese resolutions. Rao's correspondence is extended to give a bijection between even linkage a classes of subschemes of pure codimension two and stable equivalence classes of reflexive sheaves epsilon satisfying H(1)(epsilon) = 0 and epsilon chi t(1)(epsilon(V),O) = 0. Further, t hese resolutions are used to extend the work of Martin-Deschamps and P errin for Cohen-Macaulay curves in P-3 to subschemes of pure codimensi on two in P-n. In particular, even linkage classes of such subschemes satisfy the Lazarsfeld-Rao property and any minimal subscheme for an e l-en linkage class links directly to a minimal subscheme for the dual class.