2009 seminar talk: A new upper bound on the cofinality of the infinite symmetric group

Talk held by Lyubomyr Zdomskyy (KGRC) at the KGRC seminar on 2009-04-02.


We shall prove that if an ultrafilter F is not coherent to a Q-point, then cof(sym(w)) ≤ b(F).

This improves some results of J. Sharp and S. Thomas.

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Kurt Gödel Research Center for Mathematical Logic. Währinger Straße 25, 1090 Wien, Austria. Phone +43-1-4277-50501. Last updated: 2010-12-16, 04:37.