English

On convergent sequences in dual groups

General Topology 2019-10-11 v2 Functional Analysis

Abstract

We provide some characterizations of precompact abelian groups GG whose dual group GpG_p^\wedge endowed with the pointwise convergence topology on elements of GG contains a nontrivial convergent sequence. In the special case of precompact abelian \emph{torsion} groups GG, we characterize the existence of a nontrivial convergent sequence in GpG_p^\wedge by the following property of GG: \emph{No infinite quotient group of GG is countable.} Finally, we present an example of a dense subgroup GG of the compact metrizable group Z(2)ω\mathbb{Z}(2)^\omega such that GG is of the first category in itself, has measure zero, but the dual group GpG_p^\wedge does not contain infinite compact subsets. This complements Theorem 1.6 in [J.E.~Hart and K.~Kunen, Limits in function spaces and compact groups, \textit{Topol. Appl.} \textbf{151} (2005), 157--168]. As a consequence, we obtain an example of a precompact reflexive abelian group which is of the first Baire category.

Keywords

Cite

@article{arxiv.1908.03415,
  title  = {On convergent sequences in dual groups},
  author = {M. V. Ferrer and S. Hernández and M. Tkachenko},
  journal= {arXiv preprint arXiv:1908.03415},
  year   = {2019}
}
R2 v1 2026-06-23T10:43:41.767Z