On the structure of the canonical module of the Rees algebra and the associated graded ring of and ideal

Abstract

In this note we give the description of a morphism related with the structure of the canonocal module of the Rees algebra R(I) of an ideal I in a local ring . As an application we obtain Ikeda's criteria for the Gorensteinness of R(I) and a result of IierzogSimis-Vasconcelos characterizing when the canonical module of R(I) has the expected form.