A geometric perspective on local Arthur packets and some categorical implications

Geometric Representation Theory Seminar

Organizers：

Lin Chen, Will Donovan, Penghui Li, Peng Shan, Changjian Su, Wenbin Yan

Speaker：

Clifton Cunningham (University of Calgary)

Time：

Fri., 14:00-15:00, May 15, 2026

Venue：

B627, Shuangqing Complex Building A

Title：

A geometric perspective on local Arthur packets and some categorical implications

Abstract:

While Arthur packets provide a decomposition of the discrete part of L2 spectrum of automorphic representations of classical groups, their local components may be expressed purely in terms of the vanishing cycles of perverse sheaves on (part of) the stack of Langlands parameters. In this talk we explain that this follows from geometrizing twisted endoscopic transfer, done in great generality in joint work with Alexander Hazeltine, Baiying Liu, Chi-Heng Lo, Mishty Ray, Bin Xu and Jörg Schürmann. The result is a vast generalization of local Arthur packets, also providing a new tool for the study of the category of smooth representations of local groups.