Generic existence of interval P-points

Jialiang He, Renling Jin, Shuguo Zhang

Research output: Contribution to journalArticlepeer-review

Abstract

A P-point ultrafilter over ω is called an interval P-point if for every function from ω to ω there exists a set A in this ultrafilter such that the restriction of the function to A is either a constant function or an interval-to-one function. In this paper we prove the following results. (1) Interval P-points are not isomorphism invariant under CH or MA. (2) We identify a cardinal invariant non∗ ∗(Iint) such that every filter base of size less than continuum can be extended to an interval P-point if and only if non∗ ∗(Iint) = c. (3) We prove the generic existence of slow/rapid non-interval P-points and slow/rapid interval P-points which are neither quasi-selective nor weakly Ramsey under the assumption d= c or cov(B) = c.

Original languageEnglish
Pages (from-to)619-640
Number of pages22
JournalArchive for Mathematical Logic
Volume62
Issue number5-6
DOIs
StatePublished - Jul 2023
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Funding

Jialiang He: Supported in part by a National Science Foundation of China Grant #11801386. Renling Jin: Supported in part by a collaboration research Grant #513023 from Simons Foundation. Shuguo Zhang: Supported in part by a National Science Foundation of China Grant #11771311.

FundersFunder number
Simons Foundation
National Natural Science Foundation of China11771311, 513023, 1180010236, 11801386

    Keywords

    • Generic existence
    • Interval P-point
    • P-point
    • Quasi-selective ultrafilter
    • Weakly Ramsey ultrafilter

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