Work

Countable tightness is not discretely reflexive in $$\sigma$$-compact spaces

Year: 2025

Type: article

Abstract: Answering a question raised by V.V. Tkachuk in [10], we present several examples of $$\sigma$$ σ -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.

Source: Acta Mathematica Academiae Scientiarum Hungaricae

DOI: 10.1007/s10474-025-01521-7

Authors: I. Juhász, J. van Mill

Institutions: HUN-REN Alfréd Rényi Institute of Mathematics, Hungarian Research Network, University of Amsterdam

Language: English

Topic: Advanced Topology and Set Theory

Subfield: Geometry and Topology

Field: Mathematics

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,090

OpenAlex ID: W4408954758

FWCI: 1.756

Cites: 7

Cited by: 1

Related to: 10