The seminar meets on Wednesday March 13th at 11:00 in the Institute of
Mathematics CAS, Zitna 25, seminar room, 3rd floor, front building.
Program: Jonathan Verner — Towers in filters, cardinal invariants, and
Luzin type families
Jonathan will present results from his recent paper (with J. Brendle, B.
We investigate which filters on ω can contain towers, that is, a modulo
finite descending sequence without any pseudointersection. We prove the
(1) Many classical examples of nice tall filters contain no towers.
(2) It is consistent that tall analytic P-filters contain towers of
arbitrary regular height.
(3) It is consistent that all towers generate non-meager filters.
(4) The statement “Every ultrafilter contains towers.” is independent of