English

Saturation Properties of Ultrafilters in Canonical Inner Models

Logic 2025-12-10 v2

Abstract

We improve Galvin's Theorem for ultrafilters which are p-point limits of p-points. This implies that in all the canonical inner models up to a superstrong cardinal, every κ\kappa-complete ultrafilter over a measurable cardinal κ\kappa satisfies the Galvin property. On the other hand, we prove that supercompact cardinals always carry non-Galvin κ\kappa-complete ultrafilters. Finally, we prove that (κ)\diamondsuit(\kappa) implies the existence of a κ\kappa-complete filter which extends the club filter and fails to satisfy the Galvin property. This answers questions \cite[Question 5.22]{TomMotiII},\cite[Question 3.4]{Non-GalvinFil} and questions ,\cite[Question 4.5]{BenGarShe},\cite[Question 2.26]{bgp}.

Keywords

Cite

@article{arxiv.2212.14096,
  title  = {Saturation Properties of Ultrafilters in Canonical Inner Models},
  author = {Tom Benhamou},
  journal= {arXiv preprint arXiv:2212.14096},
  year   = {2025}
}