Abstract
An abelian group A is an S-group (S +-group) if every subgroup B ≤ A of finite index is A-generated (A-solvable). This article discusses some of the differences between torsion-free S-groups and mixed S-groups, and studies (mixed) S- and S +-groups, which are self-small and have finite torsion-free rank.
2000 Mathematics Subject Classification:
ACKNOWLEDGMENT
The author Simion Breaz was supported by the grant CEEX-ET19/2005–2007.
Notes
Communicated by K. M. Rangaswamy.