UBC Number Theory Seminar: Tian An Wong

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.