COHEN-MACAULAY HOMOLOGICAL DIMENSIONS WITH RESPECT TO AMALGAMATED DUPLICATION

In this paper we use \ring changed" Gorenstein homo- logical dimensions to dene Cohen-Macaulay injective, projective and at dimensions. To do this we use the amalgamated duplica- tion of the base ring with semi-dualizing ideals. Finiteness of these new dimensions characterize Cohen-Macaulay rings with dualizing ideals.