Reiner Broker

*p*-Adic class invariants

**Abstract**:
The theory of complex multiplication provides us with a means of computing a
generating polynomial for the Hilbert class field of a given imaginary
quadratic number field. The classical approach of using the modular j-function
yields polynomials with huge coefficients, and as was disovered by Weber
already, we can do better by using `smaller' functions.
In this talk we focus on new p-adic algorithms to compute such generating
polynomials. For the j-function this is based on a paper of Couveignes and
Henocq, and we explain how to generalize their approach to cope with smaller
functions over p-adic fields by using modular curves.