Article ID Journal Published Year Pages File Type
4587445 Journal of Algebra 2009 18 Pages PDF
Abstract

Let A be an Artin algebra and modA be the category of finitely generated right A-modules. We prove that an additive full subcategory C of modA closed under predecessors is contravariantly finite if and only if its right Ext-orthogonal is covariantly finite, or if and only if the Ext-injectives in C define a cotilting module (over the support algebra of C) or, equivalently, if and only if C is the support of the representable functors given by the Ext-injectives.

Related Topics
Physical Sciences and Engineering Mathematics Algebra and Number Theory