Lynn Scow : Generalized Indiscernible Sequences in stable and NIP theories.

Posted by , part of the Logic Seminar.

At

Nov. 17, 2009, 4 p.m.

In

SEO 612

Abstract

In the 1970s S. Shelah gave the following characterization of stable theories: a theory is stable if and only if any indiscernible sequence in a model of the theory is an indiscernible set. I will present a similar characterization of NIP theories, as theories in which any random ordered graph-indiscernible in a model of the theory remains indiscernible strictly with respect to the order. In this talk I will explain what I mean by a random ordered graph-indiscernible and I will indicate how the result is proved using the Nesetril-Rodl theorem. If time permits, I will discuss an additional example of a characterization of stable theories by generalized indiscernibles that generalizes more faithfully on Shelah's.

seminar begins with tea