Title: Gras conjecture, class groups and ray class groups.
Speaker: Christian Maire（Université Marie et Louis Pasteur. Institut FEMTO-ST, Besançon France.）
Time: Thursday, May 14, 2026, 10:00-11:00
Venue：Room 315, Gewu Building
Abstract:
In this talk, we begin by recalling of the conjecture of Gras.At the same time, we review the Cohen-Lenstra statistics for the class groups of quadratic fields. In both settings, valuable information can be obtained thanks to modular forms of half weight. We will explain how similar methods can applied to ray class groups of real quadratic fields. New results will be presented from joint work with Emmanuel Lecouturier (Westlake University).
