On Some Triangulated Categories Over Group Algebras
摘要
In this paper, we introduce the cofibrant derived category of a group algebra kG and study its relation to the derived category of kG. We also define the cofibrant singularity category of kG, whose triviality characterizes the regularity of kG with respect to the cofibrant dimension, and examine its significance as a measure of the obstruction to the equality between the classes of Gorenstein projective and cofibrant modules. We show that the same obstruction can be measured by certain localization sequences between stable categories.