The character spectrum of beta(N)

2010/04/13 by Saharon Shelah, Shelah, Saharon
Biochemistry, Genetics and Molecular Biology · Chemistry · Materials Science · Mathematics · #Amino Acid Enzymes and Metabolism #Enzyme Structure and Function #History and advancements in chemistry #math.GN #math.LO

paper · pdf · doi:10.48550/arxiv.1004.2083

published as Topology Appl. 158 No. 18 (2011) 2535--2555

arxiv created 2011/07/22 · arxiv updated 2011/07/26

Abstract

We show the consistency of: the set of regular cardinals which are the character of some ultrafilter on omega can be quite chaotic, in particular not only can be not convex but can have many gaps. We also deal with the set of pi-characters of ultrafilters on omega.

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