Capturing by normal ultrapowers

28.03.2019 15:00 - 16:30

M. Habič (Czech Technical U Prague, CZ and Charles U Prague, CZ)

If \(\kappa\) is measurable and GCH holds, then any ultrapower by a normal measure on \(\kappa\) will be missing some subset of \(\kappa^+\). On the other hand, Cummings showed that, starting from a \((\kappa+2)\)-strong \(\kappa\), one can force to a model (without collapsing cardinals) where \(\kappa\) carries a normal measure whose ultrapower captures the entire powerset of \(\kappa^+\). Moreover, the large cardinal hypothesis is optimal. I will present an improvement of Cummings' result and show that this capturing property can consistently hold at the least measurable cardinal.

This is joint work with Radek Honzí

Organiser:

KGRC

Location:
SR 101, 2. St., Währinger Str. 25