COLOCALIZATION FUNCTORS IN DERIVED CATEGORIES AND TORSION THEORIES.

Let R be a ring and let A be a hereditary torsion class of R-modules. The inclusion of the localizing subcategory generated by A into the derived category of R has a right adjoint, denoted CellA. Recently, Benson has shown how to compute CellA R when R is a group ring of a finite group over a prime field and A is the hereditary torsion class generated by a simple module. We generalize Benson's construction to the case where A is any hereditary torsion class on R. It is shown that for every R-module M there exists an injective R-module E such that: Hn (CellAM) ≅ Ext Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. (Hom R(M,E),E) for n ≥ 2. [ABSTRACT FROM AUTHOR]