Dave Marker : Vaught's Conjecture and Aleph_2

Posted by Matthias Aschenbrenner , part of the Logic Seminar.

At

Jan. 10, 2006, 4 p.m.

In

SEO 427

Abstract

Greg Hjorth proved that if there is a counterexample to Vaught's Conjecture, then there is one with no model of size aleph_2. The proof is an interesting mix of model theory and descriptive set theory. I will describe the proof and some of the necessary background material.