Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.

 

Past events in this series


Thu, 22 May 2025

11:00 - 12:00
C5

Modal group theory

Wojciech Wołoszyn
(University of Oxford)
Abstract

I introduce modal group theory, where one investigates the class of all groups using embeddability as a modal operator. By employing HNN extensions, I demonstrate that the modal language of groups is more expressive than the first-order language of groups. Furthermore, I establish that the theory of true arithmetic, viewed as sets of Gödel numbers, is computably isomorphic to the modal theory of finitely presented groups. Finally, I resolve an open question posed by Sören Berger, Alexander Block, and Benedikt Löwe by proving that the propositional modal validities of groups constitute precisely the modal logic S4.2.

Thu, 05 Jun 2025

11:00 - 12:00
C5

Relativistically invariant wave equations in the realist theory

Tristram de Piro
Abstract
Boris Zilber showed that you can build a logical structure around the relativistic Klein-Gordon and Dirac equations from quantum field theory. I will present the parallel realist theory, favoured by Einstein, to the Copenhagen interpretation. Starting from the requirements of Rutherford's principle for atomic systems and Maxwell's equations, I will show that there exist unique relativistically invariant wave equations for charge and current, with non-vacuum solutions.