Links of prime ideals and their Rees algebras

In a previous paper we exhibited the somewhat surprising property that most direct links of prime ideals in Gorenstein rings are equimultiple ideals with reduction number 1. This led to the construction of large families of Cohen–Macaulay Rees algebras. The first goal of this paper is to extend this result to arbitrary Cohen–Macaulay rings. The means of the proof are changed since one cannot depend so heavily on linkage theory. We then study the structure of the Rees algebra of these links, more specifically we describe their canonical module in sufficient detail to be able to characterize self–linked prime ideals. In the last section multiplicity estimates for classes of such ideals are established. AMS 1991 Mathematics Subject Classification. Primary 13H10; Secondary 13C40, 13D40, 13D45, 13H15.