Logic Seminar

Dexuan HuCornell University
Borel equivalence relations and the complexity of Lascar strong types

Friday, November 22, 2024 - 2:55pm
Malott 230

Lascar groups and Lascar strong types are well-studied objects in model theory. From a descriptive set-theoretic perspective, having the same Lascar strong type can be expressed as a Borel equivalence relationĀ on an appropriate Polish space. We provide a brief introduction to this connection and propose a framework to compare the complexity of Lascar strong types across theories. Finally, we present examples of theories that exhibit distinct levels of complexity.