ABSTRACT A module M Is said to be weakly projective If and only If It has a projective cover
11": P (M)--+ M and every map from P (M) Into a finitely generated (free) module can be …

PM Cohn [6] has defined the notion of a pure submodule. Subsequently CP Walker [21], B.
StenstrSm [19] and DP Choudhury and K. Tewari [5] have introduced notions of copurity as …

Homology groups modulo q of a precrossed P-module in any dimensions are defined in
terms of nonabelian derived functors, where q is a nonnegative integer. The Hopf formula is …

In this article, we introduce a new type of projective modules, called the weak w-projective
module. By using this type of modules, we give a homological characterization of Krull …

We approach the analysis of the extent of the projectivity of modules from a fresh perspective
as we introduce the notion of relative subprojectivity. A module M is said to be N …

NOTES ON FP-PROJECTIVE MODULES AND FP-INJECTIVE MODULES 1. Introduction
Throughout this paper, all rings are associative with id Page 1 February 17, 2006 17:49 …

A module is called locally pure-projective if every pure epimor-phism onto it is locally split.
We prove that every locally pure-projective module is a Mittag-Leffler module. We derive …

Endo-permutation modules arise in a number of ways in the representation theory of® nite
groups, in particular in connection with equivalences between blocks and as sources of …

Every QP-injective module is QPP-injective but the converse need not be true. We
investigate sufficient conditions for QPP-injective modules to be QP-injective. We show that …

The homotopy category of complexes of projective modules Page 1 Advances in Mathematics
193 (2005) 223–232 www.elsevier.com/locate/aim The homotopy category of complexes of …