English

A 0-dimensional, Lindel\"of space that is not strongly D

General Topology 2019-02-19 v1

Abstract

A topological space XX is strongly DD if for any neighbourhood assignment {Ux:xX}\{U_x:x\in X\}, there is a DXD\subseteq X such that {Ux:xD}\{U_x:x\in D\} covers XX and DD is locally finite in the topology generated by {Ux:xX}\{U_x:x\in X\}. We prove that \diamondsuit implies that there is an HFCwHFC_w space in 2ω12^{\omega_1} (hence 0-dimensional, Hausdorff and hereditarily Lindel\"of) which is not strongly DD. We also show that any HFCHFC space XX is dually discrete and if additionally, countable sets have Menger closure then XX is a DD-space.

Keywords

Cite

@article{arxiv.1902.06500,
  title  = {A 0-dimensional, Lindel\"of space that is not strongly D},
  author = {Daniel T. Soukup and Paul J. Szeptycki},
  journal= {arXiv preprint arXiv:1902.06500},
  year   = {2019}
}

Comments

14 pages, 1 figure, sumitted to Topology and its Applications