Abstract

ABSTRACTA topological space is called P2 (P3, P<ω) if and only if it does not contain two (three, finitely many) uncountable open sets with empty intersection. We show that (i) there are 0‐dimensional P<ω spaces of size 2ω, (ii) there are compact P<ω spaces of size ω1, (iii) the existence of a Ψ‐like examples for (ii) is independent of ZFC, (iv) it is consistent that 2ω is as large as you wish but every first countable (and so every compact) P2 space has cardinality ≤ω1.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.