Stable ordered-union versus selective ultrafilters

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 [6].

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Bibliographische Detailangaben
Veröffentlicht in:	Advances in mathematics (New York. 1965) 2024-12, Vol.459, p.109999, Article 109999
Hauptverfasser:	Raghavan, Dilip, Steprāns, Juris
Format:	Artikel
Sprache:	eng
Schlagworte:	Hindman's theorem Selective ultrafilter Stable ordered-union ultrafilter
Online-Zugang:	Volltext
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Beschreibung
Zusammenfassung:	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 [6].
ISSN:	0001-8708
DOI:	10.1016/j.aim.2024.109999