English

On skew ultralimits and their applications in ultrafilter theory

Logic 2026-05-12 v1

Abstract

We define a special version of the ultralimit, called the skewed ultralimit. Using this tool, we show that the set of ultrafilter types in the CC-equivalence class of a Ramsey ultrafilter uβω\mathfrak u\in \beta\omega with the Rudin-Keisler order is isomorphic to the ultrapower of (ω,)(\omega, \leq).

Keywords

Cite

@article{arxiv.2605.09714,
  title  = {On skew ultralimits and their applications in ultrafilter theory},
  author = {Nikolai L. Poliakov},
  journal= {arXiv preprint arXiv:2605.09714},
  year   = {2026}
}