1. Introduction and preliminaries. This paper deals with a generalization of the concept of
torsion Abelian groups. Our purpose is twofold. On the one hand, we treat the concept of …

In a source paper of torsion-free abelian group theory R. Baer (1) classified fully
decomposable torsion-free abelian groups, proved the Krull-Schmidt theorem for such …

This paper has two sections concerned with the characterization of the algebraic structures
of certain types of infinite abelian groups such as compact groups, or tensor products of …

In Section 0 we give an expository account of torsion theories and equivalent concepts. In
1958, Findlay and the author had studied the binary relation between modules B and C …

VI of Oregon lectures in 1962, Bass gave simplified proofs of a number of" Morita Theorems",
incorporating ideas of Chase and Schanuel. One of the Morita theorems characterizes when …

Suppose that R is a ring and that A is a chain complex over R. Inside the derived category of
differential graded R-modules there are naturally defined subcategories of A-torsion objects …

A number of sophisticated people tend to disparage category theory as consistently as
others disparage certain kinds of classical music. When obliged to speak of a category they …

Introduction. Serre has asked [5, p. 243] whether projective modules over the polynomial
ring K [Xx,•■•, Xn], K a field, are free, and Seshadri has proved that this is so when «= 2 …

Throughout the paper A will denote an artin algebra and mod A will denote the category of
finitely generated A-modules. Recently, subcategories of mod A which are the torsion free …

Throughout the book Homological algebra, by H. Cartan and S. Eilenberg, the authors dealt
with functors defined on categories of modules over certain rings and whose values again …