English

Selectivity properties of spaces

General Topology 2019-10-24 v1 Logic

Abstract

This paper addresses several questions of Feng, Gruenhage, and Shen which arose from Michael's theory of continuous selections from countable spaces. We construct an example of a space which is LL-selective but not Q\mathbb{Q}-selective from d=ω1\mathfrak{d}=\omega_1, and an LL-selective space which is not selective for a PP-point ultrafilter from the assumption of CH\mathsf{CH}. We also produce ZFC\mathsf{ZFC} examples of Fr\'echet spaces where countable subsets are first countable which are not LL-selective.

Keywords

Cite

@article{arxiv.1910.10634,
  title  = {Selectivity properties of spaces},
  author = {William Chen-Mertens and Paul J. Szeptycki},
  journal= {arXiv preprint arXiv:1910.10634},
  year   = {2019}
}
R2 v1 2026-06-23T11:52:45.303Z