Pseudoradial spaces and copies of ω1 + 1

In this paper we compare the concepts of pseudoradial spaces and the recently defined strongly pseudoradial spaces in the realm of compact spaces. We show that MA+c=ω2 implies that there is a compact pseudoradial space that is not strongly pseudoradial. We essentially construct a compact, sequential...

Full description

Saved in:
Bibliographic Details
Published in:Topology and its applications 2020-03, Vol.272, p.107070, Article 107070
Main Authors: Bella, Angelo, Dow, Alan, Hernández-Gutiérrez, Rodrigo
Format: Article
Language:English
Subjects:
Martin's axiom
Proper forcing axiom
Pseudoradial space
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In this paper we compare the concepts of pseudoradial spaces and the recently defined strongly pseudoradial spaces in the realm of compact spaces. We show that MA+c=ω2 implies that there is a compact pseudoradial space that is not strongly pseudoradial. We essentially construct a compact, sequentially compact space X and a continuous function f:X→ω1+1 in such a way that there is no copy of ω1+1 in X that maps cofinally under f. We also give some conditions that imply the existence of copies of ω1 in spaces. In particular, PFA implies that compact almost radial spaces of radial character ω1 contain many copies of ω1.
ISSN:0166-8641
1879-3207
DOI:10.1016/j.topol.2020.107070