Event Detail

Fri Mar 31, 2023
60 Evans
4:10–6 PM
Logic Colloquium
Ralf Schindler (WWU Münster)
The definability of the nonstationary ideal

We show that (a) PFA is consistent with having that NSω1 is Π1 definable and that (b) MM proves that NSω1 is not Π1 definable. Yet another time this shows that MM is the right generalization of MA. This is joint work with D. Asperó, S. Hoffelner, P. Larson, X. Sun, L. Wu.