Mathematical logic seminar - October 6 2009

Time: 12:00 - 13:20

Room: Doherty Hall 4303

Speaker:     William Boney   

Title: Model theory of L_{omega_1, omega}

Abstract: L_{omega_1, omega} is the language we get when we start with L and allow for countable conjunctions and disjunctions. Among other things, this allows us to talk about things involving finiteness and countability and allows us to omit countable types with a sentence. However, we lose the Compactness Theorem and the Upward Lowenheim-Skolem-Tarski Theorem, our two favorite methods for constructing models. In this talk, we introduce L_{omega_1, omega} and some of the model construction methods that aim to replace these.