שלחו לחבר

Stationary reflection and Prikry forcing, part 1

Seminar
Speaker
Yair Hayut (HUJI)
Date
03/03/2021 - 16:00 - 14:00
Place
Zoom
Abstract
 
In 1982, Magidor proved the consistency of stationary reflection at \aleph_{\omega+1}, relative to an \omega-sequence of supercompact cardinals. 
Square based heuristics indicated that a much weaker large cardinal hypothesis is the correct strength. 
In a sequence of results of various authors, Magidor's result was gradually improved to stationary reflection at all sets except one "bad" stationary set at \aleph_{\omega+1}, starting with a large cardinal property weaker than \kappa^+-supercompactness. 
In a joint work with Unger, we managed to obtain the consistency of (full) stationary reflection, from what seems to be close to the optimal hypothesis.
In this talk I will present the main ideas behind the proof (which is the interplay between Prikry type forcings and iterated ultrapowers). This method shares some features with the Sigma-Prikry framework, where the main difference is its non-iterative nature.
In a joint work with Ben-Neria, we tackled the problem of combining the failure of SCH with stationary reflection, starting with a similar large cardinal hypothesis. 

In order to do that, we used a similar analysis of the extender based Prikry forcing.

 

Link to video recording.

תאריך עדכון אחרון : 07/03/2021