P-spaces and the Whyburn property

  • Angelo Bella
  • , Camillo Costantini
  • , Santi Spadaro

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

We investigate the Whyburn and weakly Whyburn property in the class of P-spaces, that is spaces where every countable intersection of open sets is open. We construct examples of non-weakly Whyburn P-spaces of size continuum, thus giving a negative answer under CH to a question of Pelant, Tkachenko, Tkachuk and Wilson ([13]). In addition, we show that the weak Kurepa Hypothesis (an assumption weaker than CH) implies the existence of a non-weakly Whyburn P-space of size N2. Finally, we consider the behavior of the above-mentioned properties under products; we show in particular that the product of a Lindelöf weakly Whyburn P-space and a Lindelöf Whyburn P-space is weakly Whyburn, and we give a consistent example of a non-Whyburn product of two Lindelöf Whyburn P-spaces.

Original languageEnglish
Pages (from-to)995-1015
Number of pages21
JournalHouston Journal of Mathematics
Volume37
Issue number3
StatePublished - 26 Dec 2011

Keywords

  • Almost disjoint family
  • Cardinality
  • Continuum hypothesis
  • Extent
  • Lindelöf space
  • Nowhere mad family
  • P-space
  • Pseudocharacter
  • Pseudoradial space
  • Radial character
  • Radial space
  • Weak Kurepa tree
  • Weakly Whyburn space
  • Weight
  • Whyburn space
  • ω-Modification

ASJC Scopus subject areas

  • General Mathematics

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