Last week we started a new topic, it will be continued tomorrow afternoon on Monday November 5th.

As several people missed the first talk, Roy summarized the first talk here.

The original announcement:

**Roy Jiang**

**Carnegie Mellon University**

**Title:**Many models for unstable first-order theory, part 2

** Abstract: **In this sequence of lecture I will prove Shelah’s celebrated

Theorem. Let T be a first-order theory and \lambda be an uncountable cardinal satisfying \lambda >= |T|. If T is unstable then I(\lambda,T)=2^\lambda.

For the proof we will construct many “complicated” linear orders, we will take Skolem hulls of such orders and if I(\lambda,T)<2^\lambda using combinatorial set theory we will construct large families of almost disjoint sets and will use them to code stationary sets into isomorphism types of models for T.

**Date: **Monday, November 5, 2012

**Time: ** 5:00 pm

**Location: ** Wean 8220