Ruiyuan (Ronnie) Chen : Polish groupoids and $\mathcal{L}_{\omega_1\omega}$-theories

Posted by Filippo Calderoni , part of the Logic Seminar.

At

Oct. 15, 2019, 3:30 p.m.

In

427 SEO

Abstract

It is well-known that countable infinitary model theory is closely related to the dynamics of non-Archimedean Polish groups. We extend this correspondence by showing that there is a complete (2-categorical) equivalence between countable $\mathcal{L}_{\omega_1\omega}$-theories and their open non-Archimedean Polish groupoids of countable models. We will also discuss the extension of this correspondence to continuous logic.