Logic Seminar

Strong conceptual completeness (SCC) theorems allow the syntax of a logical theory to be canonically recovered from its space of models equipped with suitable structure, and are known for finitary first-order logic (Makkai) and fragments thereof (Gabriel-Ulmer, Lawvere, and others). In this talk, I will present a SCC theorem for L_{\omega_1\omega}: a countable L_{\omega_1\omega}-theory can be recovered from its standard Borel groupoid of countable models.