Filtrations of Totally Reflexive Modules
  In this paper, we will introduce a subcategory of totally reflexive modules that have a saturated filtration by other totally reflexive modules. We will prove these are precisely the totally reflexive modules with an upper-triangular presentation matrix. We conclude with an investigation of the ranks of $\operatorname{Ext}^1$ of two such modules over a specific ring. 
Denise A. Rangel Tracy
math.AC math.RT