The spectrum of characters of ultrafilters on ω
Saharon Shelah
Colloquium Mathematicae, Tome 111 (2008), p. 213-220 / Harvested from The Polish Digital Mathematics Library
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We show the consistency of the statement: "the set of regular cardinals which are the characters of ultrafilters on ω is not convex". We also deal with the set of π-characters of ultrafilters on ω.

Publié le : 2008-01-01
EUDML-ID : urn:eudml:doc:283906 
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     title = {The spectrum of characters of ultrafilters on $\omega$},
     journal = {Colloquium Mathematicae},
     volume = {111},
     year = {2008},
     pages = {213-220},
     zbl = {1142.03028},
     language = {en},
     url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm111-2-5}
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Saharon Shelah. The spectrum of characters of ultrafilters on ω. Colloquium Mathematicae, Tome 111 (2008) pp. 213-220. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm111-2-5/