Set theory workshop
Nam Trang
UC Irvine
Compactness of $\omega_1$
Abstract: We investigate various aspects of compactness of $\omega_1$ under ZF + DC. We say that $\omega_1$ is X-supercompact if there is a normal, fine, countably complete nonprincipal measure on $\mathcal{P}_{\omega_1}(X)$ (in the sense of Solovay). We say $\omega_1$ is X-strongly compact if there is a fine, countably complete nonprincipal measure on $\mathcal{P}_{\omega_1}(X)$. We discuss various results in constructing and analyzing canonical models of $AD^+$ + $\omega_1$ is (X)-supercompact. We also discuss whether the theories "$\omega_1$ is X-supercompact" and "$\omega_1$ is X-strongly compact" can be equiconsistent for various X.
Friday October 21, 2016 at 4:00 PM in SEO 636