Logic Seminar
Maryanthe Malliaris
UCBerkeley
Characteristic sequences and Keisler's order
Abstract: A natural and deep move in model theory is to classify theories into complexity classes according to various, often quite coarse, criteria. If all goes well these criteria act as a kind of scaffolding: they call attention to deep structural properties of the underlying models or theories which, it turns out, can already be seen locally within the theory. Shelah's stability theory (counting types over sets) is a beautiful and well-known example. Keisler's order might be another, but parts of its structure have remained elusive.
The talk will have two complimentary parts: on one hand, I'll describe recent progress on Keisler's order and the structure theory it suggests, and on the other, a project to build from within first-order theories a framework in which these basic combinatorial issues are visible and can be analyzed.
seminar begins with tea.
Wednesday January 14, 2009 at 4:00 PM in SEO 612