Towards a notion of mesoscopy

This talk will take place in-person and online.
Zoom link: https://ubc.zoom.us/j/9396078403?pwd=uD6PhmyITsV6zRioCOXydK1YTgDB0p.1
Zoom ID: 939 607 8403
password: 004133

Within the Langlands program, the theory of endoscopy concerns the transfer of distributions between a reductive group $G$ and $G'$, an endoscopic group of $G$. At the heart of Langlands' original study on Beyond Endoscopy is the notion of stable transfer between groups $G$ and $G'$, where $G'$ is no longer required to be an endoscopic group. Arthur referred to these as 'beyond endoscopic groups,' and which we call mesoscopic groups. In this talk I will introduce these ideas, the role they play in functoriality, and open problems that arise in their study. Time permitting, I will explain the role they play in refining the stable trace formula.