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A TORSION-FREE ABELIAN GROUP EXISTS WHOSE QUOTIENT GROUP MODULO THE SQUARE SUBGROUP IS NOT A NIL-GROUP

Published online by Cambridge University Press:  30 August 2016

R. R. ANDRUSZKIEWICZ*
Affiliation:
Institute of Mathematics, University of Białystok, 15-267 Białystok, K. Ciołkowskiego 1M, Poland email randrusz@math.uwb.edu.pl
M. WORONOWICZ
Affiliation:
Institute of Mathematics, University of Białystok, 15-267 Białystok, K. Ciołkowskiego 1M, Poland email mworonowicz@math.uwb.edu.pl
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Abstract

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The first example of a torsion-free abelian group $(A,+,0)$ such that the quotient group of $A$ modulo the square subgroup is not a nil-group is indicated (for both associative and general rings). In particular, the answer to the question posed by Stratton and Webb [‘Abelian groups, nil modulo a subgroup, need not have nil quotient group’, Publ. Math. Debrecen27 (1980), 127–130] is given for torsion-free groups. A new method of constructing indecomposable nil-groups of any rank from $2$ to $2^{\aleph _{0}}$ is presented. Ring multiplications on $p$-pure subgroups of the additive group of the ring of $p$-adic integers are investigated using only elementary methods.

Type
Research Article
Copyright
© 2016 Australian Mathematical Publishing Association Inc. 

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