THICK SUBCATEGORIES AND VIRTUALLY GORENSTEIN ALGEBRAS

摘要

An Artin algebra is by definition virtually Gorenstein if the class of modules which are right orthogonal (with respect to Ext~*(-,-)) to all Gorenstein projective modules coincides with the class of modules which are left orthogonal to all Gorenstein injective modules. We provide a new characterization in terms of finitely generated modules. In addition, an example of an algebra is presented which is not virtually Gorenstein.