AD$^+$ implies that $\omega_1$ is a $\Theta$-Berkeley cardinal
Abstract
Following \cite{bagaria2019large}, given cardinals , we say is a club -Berkeley cardinal if for every transitive set of size such that , there is a club with the property that for every there is an elementary embedding with crit. We say is -club -Berkeley if as above is a -club. We say is -Berkeley if is unbounded in . We show that under AD, (1) every regular Suslin cardinal is -club -Berkeley (see \rthm{main theorem}), (2) is club -Berkeley (see \rthm{main theorem lr} and \rthm{main theorem}), and (3) the 's are -Berkeley -- in particular, is -Berkeley (see \rrem{omega2}). Along the way, we represent regular Suslin cardinals in direct limits as cutpoint cardinals (see \rthm{char extenders}). This topic has been studied in \cite{MPSC} and \cite{jackson2022suslin}, albeit from a different point of view. We also show that, assuming , is not -Berkeley, so the result stated in the title is optimal (see \rthm{lr optimal} and \rthm{thetareg optimal}).
Cite
@article{arxiv.2402.01329,
title = {AD$^+$ implies that $\omega_1$ is a $\Theta$-Berkeley cardinal},
author = {Douglas Blue and Grigor Sargsyan},
journal= {arXiv preprint arXiv:2402.01329},
year = {2025}
}