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Le problème de Lehmer relatif en dimension supérieure

Emmanuel Delsinne (2009)

Annales scientifiques de l'École Normale Supérieure

Nous généralisons en dimension supérieure un théorème d’Amoroso et Zannier concernant le problème de Lehmer relatif. Nous minorons la hauteur d’un point d’un tore en fonction de son indice d’obstruction sur ab , l’extension abélienne maximale de , à condition qu’il ne soit pas contenu dans une sous-variété de torsion de petit degré. Nous en déduisons une minoration du minimum essentiel d’une sous-variété non contenue dans un sous-groupe algébrique propre en fonction de son indice d’obstruction sur...

Maximal unramified extensions of imaginary quadratic number fields of small conductors, II

Ken Yamamura (2001)

Journal de théorie des nombres de Bordeaux

In the previous paper [15], we determined the structure of the Galois groups Gal ( K u r / K ) of the maximal unramified extensions K u r of imaginary quadratic number fields K of conductors 1000 under the Generalized Riemann Hypothesis (GRH) except for 23 fields (these are of conductors 723 ) and give a table of Gal ( K u r / K ) . We update the table (under GRH). For 19 exceptional fields K of them, we determine Gal ( K u r / K ) . In particular, for K = 𝐐 ( - 856 ) , we obtain Gal ( K u r / K ) S 4 ˜ × C 5 and K u r = K 4 , the fourth Hilbert class field of K . This is the first example of a number field whose...

Nombre d'extensions abéliennes sur Q

Artur Travesa (1990)

Journal de théorie des nombres de Bordeaux

The aim of this paper is to give the numbers of abelian number fields with given degree and ramification indices. We describe, also, an algorithm to compute all these fields.

Non-existence and splitting theorems for normal integral bases

Cornelius Greither, Henri Johnston (2012)

Annales de l’institut Fourier

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 K L forces the tower to be split in a very strong sense.

Note on the congruence of Ankeny-Artin-Chowla type modulo p²

Stanislav Jakubec (1998)

Acta Arithmetica

The results of [2] on the congruence of Ankeny-Artin-Chowla type modulo p² for real subfields of ( ζ p ) of a prime degree l is simplified. This is done on the basis of a congruence for the Gauss period (Theorem 1). The results are applied for the quadratic field ℚ(√p), p ≡ 5 (mod 8) (Corollary 1).

Note on the Hilbert 2-class field tower

Abdelmalek Azizi, Mohamed Mahmoud Chems-Eddin, Abdelkader Zekhnini (2022)

Mathematica Bohemica

Let k be a number field with a 2-class group isomorphic to the Klein four-group. The aim of this paper is to give a characterization of capitulation types using group properties. Furthermore, as applications, we determine the structure of the second 2-class groups of some special Dirichlet fields 𝕜 = ( d , - 1 ) , which leads to a correction of some parts in the main results of A. Azizi and A. Zekhini (2020).

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