Logic Seminar
Dima Sinapova
UIC
Singularizing and square
Abstract: It is an old theorem that if a regular cardinal is singularized to have cofinality $\omega$, while preserving cardinals, then $\square_{\kappa, \omega}$ holds in the outer model.
We will show that this does not generalize to uncountable cofinalities.
In particular, we show that after the right kind of preparation, in the Magidor model of
singularizing $\kappa$ to uncountable cofinality all intermediate forms of square at $\kappa$ fail. This is joint work with Maxwell Levine.
Tuesday April 9, 2019 at 3:30 PM in 427 SEO