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Direct sums and refinement. (English) Zbl 0920.20045

A set \(A\) of objects in an additive category has the refinement property if every direct summand of a direct sum of objects in \(A\) is isomorphic to a direct sum of objects of \(A\). This situation is frequently considered in the theory of torsion-free abelian groups of finite rank, in which the refinement property can be used as a substitute for the Krull-Schmidt Theorem or Kaplansky’s Test Problems.
The author proves that various classes of finite rank torsion-free abelian groups have the refinement property in categories whose isomorphisms are near- or quasi-isomorphisms of abelian groups.
Reviewer: Ph.Schultz (Perth)

MSC:

20K25 Direct sums, direct products, etc. for abelian groups
20K15 Torsion-free groups, finite rank
20K40 Homological and categorical methods for abelian groups
Full Text: DOI

References:

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