English

Maximally almost periodic groups and respecting properties

General Topology 2018-04-05 v4

Abstract

For a Tychonoff space XX, denote by P\mathfrak{P} the family of topological properties P\mathcal{P} of being a convergent sequence or being a compact, sequentially compact, countably compact, pseudocompact and functionally bounded subset of XX, respectively. A maximally almost periodic (MAP(MAP) group GG respects P\mathcal{P} if P(G)=P(G+)\mathcal{P}(G)=\mathcal{P}(G^+), where G+G^+ is the group GG endowed with the Bohr topology. We study relations between different respecting properties from P\mathfrak{P} and show that the respecting convergent sequences (=the Schur property) is the weakest one among the properties of P\mathfrak{P}. We characterize respecting properties from P\mathfrak{P} in wide classes of MAPMAP topological groups including the class of metrizable MAPMAP abelian groups. Every real locally convex space (lcs) is a quotient space of an lcs with the Schur property, and every locally quasi-convex (lqc) abelian group is a quotient group of an lqc abelian group with the Schur property. It is shown that a reflexive group GG has the Schur property or respects compactness iff its dual group GG^\wedge is c0c_0-barrelled or gg-barrelled, respectively. We prove that a locally quasi-convex abelian kωk_\omega-group respects all properties PP\mathcal{P}\in\mathfrak{P}. As an application of the obtained results we show that (1) the space Ck(X)C_k(X) is a reflexive group for every separable metrizable space XX, and (2) a reflexive abelian group of finite exponent is a Mackey group.

Keywords

Cite

@article{arxiv.1712.05521,
  title  = {Maximally almost periodic groups and respecting properties},
  author = {Saak Gabriyelyan},
  journal= {arXiv preprint arXiv:1712.05521},
  year   = {2018}
}
R2 v1 2026-06-22T23:18:49.186Z