In this paper, we introduce and study the notion of linkage modules by reflexive homomorphisms. This unifies generalizes several known concepts enables us to theory over Cohen–Macaulay rings rather than more restrictive Gorenstein rings. It is shown that results for are still true in general case module We also colinkage establish an adjoint equivalence between linked colinked modules.

We study one-dimensional Cohen-Macaulay rings whose trace ideal of the canonical module is as small possible. In this paper we call such far-flung Gorenstein rings. investigate in relation with endomorphism algebras maximal ideals and numerical semigroup show that solution Rohrbach problem additive number theory provides an upper bound for multiplicity Reflexive modules over are also studied.

We exhibit the elementary but somewhat surprising property that most direct links of prime ideals in Gorenstein rings are equimultiple ideals. It leads to the construction of a bountiful set of Cohen–Macaulay Rees algebras.

The main aim of this paper is to find a large class of rings for which there are indecomposable maximal Cohen-Macaulay modules of arbitrary high multiplicity (or rank in the case of domains).