Mathematical logic seminar - October 27, 2015

Time: 12:30 - 13:30

Room: Wean Hall 7201

Speaker:     Bill Chen    
Department of Mathematics

Title: Can every mutually stationary sequence be tightly stationary?

Abstract: Mutual and tight stationarity are two notions of stationarity defined on certain products associated to a singular cardinal, introduced by Foreman and Magidor. Tight stationarity is closely related to the structure of scales at the singular cardinal, whereas mutual stationarity has a more mysterious, model-theoretic character. In this talk, I will investigate the question of Cummings, Foreman, and Magidor of whether every mutually stationary sequence can be tightly stationary. The main result is a model where mutual and tight stationarity are distinct everywhere (joint with Itay Neeman).