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.
A new upper bound on the cofinality of the infinite symmetric group
02.04.2009 15:00 - 16:30
Organiser:
KGRC
Location:
SR 101, 2. St., Währinger Str. 25