$\textsf {AD}^{+}$ implies $ \omega _{1}$ is a club $ \Theta $ -Berkeley cardinal

Following [1], given cardinals $\kappa <\lambda $ , we say $\kappa $ is a club $\lambda $ -Berkeley cardinal if for every transitive set N of size $<\lambda $ such that $\kappa \subseteq N$ , there is a club $C\subseteq \kappa $ with the property that for...

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Main Authors: Douglas Blue, Grigor Sargsyan
Format: Article
Language:English
Published: Cambridge University Press 2025-01-01
Series:Forum of Mathematics, Sigma
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Online Access:https://www.cambridge.org/core/product/identifier/S2050509425100820/type/journal_article
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author Douglas Blue
Grigor Sargsyan
author_facet Douglas Blue
Grigor Sargsyan
author_sort Douglas Blue
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description Following [1], given cardinals $\kappa <\lambda $ , we say $\kappa $ is a club $\lambda $ -Berkeley cardinal if for every transitive set N of size $<\lambda $ such that $\kappa \subseteq N$ , there is a club $C\subseteq \kappa $ with the property that for every $\eta \in C$ , there is an elementary embedding $j: N\rightarrow N$ with $\mathrm {crit }(j)=\eta $ . We say $\kappa $ is $\nu $ -club $\lambda $ -Berkeley if $C\subseteq \kappa $ as above is a $\nu $ -club. We say $\kappa $ is $\lambda $ -Berkeley if C is unbounded in $\kappa $ . We show that under $\textsf {AD}^{+}$ , (1) every regular Suslin cardinal is $\omega $ -club $\Theta $ -Berkeley (see Theorem 7.1), (2) $\omega _1$ is club $\Theta $ -Berkeley (see Theorem 3.1 and Theorem 7.1), and (3) the ’s are $\Theta $ -Berkeley – in particular, $\omega _2$ is $\Theta $ -Berkeley (see Remark 7.5).
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spelling doaj-art-ebde432cf09242559d078db52cbcc7b92025-08-20T02:47:58ZengCambridge University PressForum of Mathematics, Sigma2050-50942025-01-011310.1017/fms.2025.10082$\textsf {AD}^{+}$ implies $ \omega _{1}$ is a club $ \Theta $ -Berkeley cardinalDouglas Blue0https://orcid.org/0000-0003-1217-9215Grigor Sargsyan1https://orcid.org/0000-0002-6095-1997Department of Philosophy, https://ror.org/01an3r305University of Pittsburgh, 1017 Cathedral of Learning, Pittsburgh, PA, 15260, USAhttps://ror.org/04hrrh248Institute of Mathematics of Polish Academy of Sciences, ul. Śniadeckich 8, Warszawa, 00-656, Poland; E-mail:Following [1], given cardinals $\kappa <\lambda $ , we say $\kappa $ is a club $\lambda $ -Berkeley cardinal if for every transitive set N of size $<\lambda $ such that $\kappa \subseteq N$ , there is a club $C\subseteq \kappa $ with the property that for every $\eta \in C$ , there is an elementary embedding $j: N\rightarrow N$ with $\mathrm {crit }(j)=\eta $ . We say $\kappa $ is $\nu $ -club $\lambda $ -Berkeley if $C\subseteq \kappa $ as above is a $\nu $ -club. We say $\kappa $ is $\lambda $ -Berkeley if C is unbounded in $\kappa $ . We show that under $\textsf {AD}^{+}$ , (1) every regular Suslin cardinal is $\omega $ -club $\Theta $ -Berkeley (see Theorem 7.1), (2) $\omega _1$ is club $\Theta $ -Berkeley (see Theorem 3.1 and Theorem 7.1), and (3) the ’s are $\Theta $ -Berkeley – in particular, $\omega _2$ is $\Theta $ -Berkeley (see Remark 7.5).https://www.cambridge.org/core/product/identifier/S2050509425100820/type/journal_article03E6003E5503E4503E57
spellingShingle Douglas Blue
Grigor Sargsyan
$\textsf {AD}^{+}$ implies $ \omega _{1}$ is a club $ \Theta $ -Berkeley cardinal
Forum of Mathematics, Sigma
03E60
03E55
03E45
03E57
title $\textsf {AD}^{+}$ implies $ \omega _{1}$ is a club $ \Theta $ -Berkeley cardinal
title_full $\textsf {AD}^{+}$ implies $ \omega _{1}$ is a club $ \Theta $ -Berkeley cardinal
title_fullStr $\textsf {AD}^{+}$ implies $ \omega _{1}$ is a club $ \Theta $ -Berkeley cardinal
title_full_unstemmed $\textsf {AD}^{+}$ implies $ \omega _{1}$ is a club $ \Theta $ -Berkeley cardinal
title_short $\textsf {AD}^{+}$ implies $ \omega _{1}$ is a club $ \Theta $ -Berkeley cardinal
title_sort textsf ad implies omega 1 is a club theta berkeley cardinal
topic 03E60
03E55
03E45
03E57
url https://www.cambridge.org/core/product/identifier/S2050509425100820/type/journal_article
work_keys_str_mv AT douglasblue textsfadimpliesomega1isaclubthetaberkeleycardinal
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