Exceptional varieties built from exceptional reflection groups

Geometric Representation Theory Seminar

Organizers：

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

Speaker：

Cédric Bonnafé

(IMAG, Université de Montpellier)

Time：

Mon., 3:30-4:30 pm, Mar. 23, 2026

Venue：

B627, Shuangqing Complex Building

Title:

Exceptional varieties built from exceptional reflection groups

Abstract:

There are many ways for a variety to be "exceptional", but we focus in this talk on some old problems in classical algebraic geometry: finding curves and surfaces with many singular points, with big automorphism groups, finding surfaces with many lines or conics, finding K3 surfaces with big Picard numbers... We present a series of examples, all built from invariants of exceptional complex reflection groups, which are up to now the records in their own categories.