The Koponen Conjecture

This is on joint work with John Baldwin and James Freitag.

One of the central projects of model theory, initiated by Shelah in his book "Classification Theory," is to classify unstable first-order theories. As part of this program, Koponen proposes to classify simple homogeneous structures, such as the random graph. More precisely, she conjectures (2016) that all simple theories with quantifier elimination in a finite relational language are supersimple of finite rank, and asks (2014) whether they are one-based. In this talk, we discuss our resolution of the Koponen conjecture, where we show that the answer to this question is yes. In the process, we further demonstrate what Kennedy (2020) calls ''the fragility of the syntax-semantics distinction.”