
Abstract: The aim of this series of 3 talks is to report on
I. Siegel's result on the rationality of the values L(1  k; \epsilon), k > 0, of certain Lfunctions over totally real number fields to be
defined later and
II. the congruences among those values which have been shown by
Deligne and Ribet and which amount to the existence of padic
Lfunctions.
