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On t-pure and almost pure exact sequences of LCA groups

  • Peter Loth EMAIL logo
Published/Copyright: February 12, 2007
Journal of Group Theory
From the journal Volume 9 Issue 6

Abstract

A proper short exact sequence

in the category of locally compact abelian groups is said to be t-pure if φ(A) is a topologically pure subgroup of B, that is, if

for all positive integers n. We establish conditions under which t-pure exact sequences split and determine those locally compact abelian groups KD (where K is compactly generated and D is discrete) which are t-pure injective or t-pure projective. Calling the extension (*) almost pure if

for all positive integers n, we obtain a complete description of the almost pure injectives and almost pure projectives in the category of locally compact abelian groups.


(Communicated by R. Göbel)


Received: 2005-08-28
Revised: 2005-12-06
Published Online: 2007-02-12
Published in Print: 2006-11-28

© Walter de Gruyter

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