Almost locally free groups and the genus question
摘要
Sacerdote [Sa] has shown that the non-Abelian free groups satisfy precisely the same universal-existential sentences Th(F) in a first-order language L appropriate for group theory. It is shown that in every model of Th(F) the maximal Abelian subgroups are elementarily equivalent to locally cyclic groups (necessarily nontrivial and torsion free). Two classes of groups are interpolated between the non-Abelian locally free groups and Remeslennikov's -free groups. These classes are the \textbf{almost locally free groups} and the \textbf{quasi-locally free groups}. In particular, the almost locally free% \textbf{\ }groups are the models of Th(F) while the quasi-locally free groups are the -free groups with maximal Abelian subgroups elemenatarily equivalent to locally cyclic groups (necessarily nontrivial and torsion free). Two principal open questions at opposite ends of a spectrum are: (1.) Is every finitely generated almost locally free group free? (2.) Is every quasi-locally free group almost locally free? Examples abound of finitely generated quasi-locally free groups containing nontrivial torsion in their Abelianizations. The question of whether or not almost locally free groups have torsion free Abelianization is related to a bound in a free group on the number of factors needed to express certain elements of the derived group as a product of commutators.
引用
@article{arxiv.math/9603204,
title = {Almost locally free groups and the genus question},
author = {Anthony Gaglione and Dennis Spellman},
journal= {arXiv preprint arXiv:math/9603204},
year = {2009}
}
备注
DVI and Post-Script files only