On Chinburg's second conjecture for abelian fields.
Sur les normes universelles dans les -extensions
Über relativ-invariante Kreiseinheiten und Stickelberger-Elemente.
On normal integral bases in ray class fields over imaginary quadratic fields
Tate sequences and lower bounds for ranks of class groups
Tate sequences play a major role in modern algebraic number theory. The extension class of a Tate sequence is a very subtle invariant which comes from class field theory and is hard to grasp. In this short paper we demonstrate that one can extract information from a Tate sequence without knowing the extension class in two particular situations. For certain totally real fields K we will find lower bounds for the rank of the ℓ-part of the class group Cl(K), and for certain CM fields we will find lower...
Class groups of abelian fields, and the main conjecture
This first part of this paper gives a proof of the main conjecture of Iwasawa theory for abelian base fields, including the case , by Kolyvagin’s method of Euler systems. On the way, one obtains a general result on local units modulo circular units. This is then used to deduce theorems on the order of -parts of -class groups of abelian number fields: first for relative class groups of real fields (again including the case ). As a consequence, a generalization of the Gras conjecture is stated...
Galois-Cohen-Lenstra heuristics
On totally real Hilbert-Speiser fields of type Cₚ
Eigenspaces of the ideal class group
The aim of this paper is to prove an analog of Gras’ conjecture for an abelian field and an odd prime dividing the degree assuming that the -part of group is cyclic.
Non-existence and splitting theorems for normal integral bases
We establish new conditions that prevent the existence of (weak) normal integral bases in tame Galois extensions of number fields. This leads to the following result: under appropriate technical hypotheses, the existence of a normal integral basis in the upper layer of an abelian tower forces the tower to be split in a very strong sense.
Annihilators of minus class groups of imaginary abelian fields
For certain imaginary abelian fields we find annihilators of the minus part of the class group outside the Stickelberger ideal. Depending on the exact situation, we use different techniques to do this. Our theoretical results are complemented by numerical calculations concerning borderline cases.
The lifted root number conjecture for fields of prime degree over the rationals: an approach via trees and Euler systems
The so-called Lifted Root Number Conjecture is a strengthening of Chinburg’s - conjecture for Galois extensions of number fields. It is certainly more difficult than the -localization. Following the lead of Ritter and Weiss, we prove the Lifted Root Number Conjecture for the case that and the degree of is an odd prime, with another small restriction on ramification. The very explicit calculations with cyclotomic units use trees and some classical combinatorics for bookkeeping. An important...
Racines d'unités cyclotomiques et divisibilité du nombre de classes d'un corps abélien réel
Equivariant Weierstrass preparation and values of -functions at negative integers.
Page 1