Stable ordered-union versus selective ultrafilters
Logic
2023-10-24 v2 Combinatorics
General Topology
Abstract
It will be shown to be consistent that there are at least two non-isomorphic selective ultrafilters, but no stable ordered-union ultrafilters. This answers a question of Blass from his 1987 paper which introduced the concept of a stable ordered-union ultrafilter.
Keywords
Cite
@article{arxiv.2302.05539,
title = {Stable ordered-union versus selective ultrafilters},
author = {Dilip Raghavan and Juris Steprans},
journal= {arXiv preprint arXiv:2302.05539},
year = {2023}
}
Comments
42 pages. Submitted. Minor revisions made