(Strongly) Gorenstein Flat Modules Over Group rings

Abstract

Let Γ be a group and Γ be a subgroup of Γ of finite index. Let M be a Γ-module. It is shown that M is (strongly) Gorenstein flat if and only if it is (strongly) Gorenstein flat as a Γ -module. We also provide some criteria in which the classes of Gorenstein projective and strongly Gorenstein flat Γ-modules are the same.2010 Mathematics subject classification: primary 20J05, 16D40; secondary 16S34.