Videos

Averages of p-torsion in class groups over function fields---good and bad primes

Presenter
May 1, 2017
Keywords:
  • class field theory
  • Cohen-Lenstra statistics
  • function fields
  • p-torsion
  • quadratic fields
MSC:
  • 11R29
  • 11N36
  • 11R45
  • 11R58
  • 11R99
Abstract
When we consider the average size of the p-torsion in class groups of quadratic fields, the behavior for p=2 is controlled by genus theory and is different from the conjectured behavior for odd primes, which is uniform in a certain sense over all odd primes. In this talk, we will consider the question when quadratic fields are replaced by fields of higher degree--for which primes p are the class group averages "bad" versus "good"? We will explain some theorems on class group averages for extensions of function fields that show some subtleties in the classification of good and bad primes