# Sh:915

• Shelah, S. (2011). The character spectrum of \beta(\mathbb N). Topology Appl., 158(18), 2535–2555.
• 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
• Current version: 2011-09-22_12 (31p) published version (21p)
Bib entry
@article{Sh:915,
author = {Shelah, Saharon},
title = {{The character spectrum of $\beta(\mathbb N)$}},
journal = {Topology Appl.},
fjournal = {Topology and its Applications},
volume = {158},
number = {18},
year = {2011},
pages = {2535--2555},
issn = {0166-8641},
mrnumber = {2847327},
mrclass = {03E35 (03E17 03E55 54A25)},
doi = {10.1016/j.topol.2011.08.014},
note = {\href{https://arxiv.org/abs/1004.2083}{arXiv: 1004.2083}},
arxiv_number = {1004.2083}
}