English

Measures that violate the Generalized Continuum Hypothesis

Logic 2025-12-10 v2

Abstract

A simple PλP_\lambda-point on a regular cardinal κ\kappa is a uniform ultrafilter on κ\kappa with a mod-bounded decreasing generating sequence of length λ\lambda. We prove that if there is a simple PλP_\lambda-point ultrafilter over κ>ω\kappa>\omega, then λ=dκ=bκ=uκ=rκ=sκ\lambda=\mathfrak{d}_\kappa=\mathfrak{b}_\kappa=\mathfrak{u}_\kappa=\mathfrak{r}_\kappa=\mathfrak{s}_\kappa. We show that such ultrafilters appear in the models of \cite{SimonOmer,BROOKETAYLOR201737}. We improve the lower bound for the consistency strength of the existence of a Pκ++P_{\kappa^{++}}-point to a 22-strong cardinal. Finally, we apply our arguments to obtain non-trivial lower bounds for (1) the statement that the generalized tower number tκ\mathfrak{t}_\kappa is greater than κ+\kappa^+ and κ\kappa is measurable, (2) the preservation of measurability after the generalized Mathias forcing, and (3) variations of filter games of \cite{NIELSEN_WELCH_2019,HolySchlicht:HierarchyRamseyLikeCardinals,MagForZem} in the case 2κ>κ+2^\kappa>\kappa^+.

Keywords

Cite

@article{arxiv.2503.20094,
  title  = {Measures that violate the Generalized Continuum Hypothesis},
  author = {Tom Benhamou and Gabriel Goldberg},
  journal= {arXiv preprint arXiv:2503.20094},
  year   = {2025}
}
R2 v1 2026-06-28T22:34:29.621Z