Countable tightness is not discretely reflexive in $\sigma$-compact spaces
Abstract
Answering a question raised by V. V. Tkachuk, we present several examples of $\sigma$-compact spaces, some only consistent and some in ZFC, that are not countably tight but in which the closure of any discrete subset is countably tight. In fact, in some of our examples the closures of all discrete subsets are even first countable.
- Publication:
-
arXiv e-prints
- Pub Date:
- November 2024
- DOI:
- arXiv:
- arXiv:2411.04523
- Bibcode:
- 2024arXiv241104523J
- Keywords:
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- Mathematics - General Topology;
- 54A25;
- 54A35;
- 54D45
- E-Print:
- 7 pages