Greg Cousins : A Homotopical View of Lascar Groups of First-Order Theories

Posted by James Freitag , part of the Logic Seminar.

At

Sept. 25, 2018, 3:30 p.m.

In

427 SEO

Abstract

In this talk, we will discuss how the Lascar group of a first-order theory, $T$, can be recovered as the fundamental group(-oid) of a certain space associated to the category of models, $\operatorname{Mod}(T)$. We will then discuss some examples illustrating how tools from algebraic topology can be used to compute the Lascar group of a theory. Time permitting, we will discuss generalizations to the context of AECs and questions their higher homotopy. No knowledge of homotopy theory will be assumed. This is joint work with Tim Campion and Jinhe Ye.