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The minimal cofinality of an ultrapower of ω and the cofinality of the symmetric group can be larger than b+

Published online by Cambridge University Press:  12 March 2014

Heike Mildenberger
Abteilung für Mathematische Logik, Mathematisches Institut, Universität Freiburg, Eckerstr. 1, 79104 Freiburg im Breisgau, Germany, E-mail:
Saharon Shelah
Einstein Institute of Mathematics, The Hebrew University, Edmond Safra Campus Givat Ram, Jerusalem 91904, Israel, E-mail:


We prove the statement in the title.

Research Article
Copyright © Association for Symbolic Logic 2011

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