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Failure of the Hasse principle for Châtelet surfaces in characteristic 2

Bianca Viray (2012)

Journal de Théorie des Nombres de Bordeaux

Given any global field k of characteristic 2 , we construct a Châtelet surface over k that fails to satisfy the Hasse principle. This failure is due to a Brauer-Manin obstruction. This construction extends a result of Poonen to characteristic 2 , thereby showing that the étale-Brauer obstruction is insufficient to explain all failures of the Hasse principle over a global field of any characteristic.

Families of hypersurfaces of large degree

Christophe Mourougane (2012)

Journal of the European Mathematical Society

Grauert and Manin showed that a non-isotrivial family of compact complex hyperbolic curves has finitely many sections. We consider a generic moving enough family of high enough degree hypersurfaces in a complex projective space. We show the existence of a strict closed subset of its total space that contains the image of all its sections.

Field of moduli versus field of definition for cyclic covers of the projective line

Aristides Kontogeorgis (2009)

Journal de Théorie des Nombres de Bordeaux

We give a criterion, based on the automorphism group, for certain cyclic covers of the projective line to be defined over their field of moduli. An example of a cyclic cover of the complex projective line with field of moduli that can not be defined over is also given.

Fields of definition of -curves

Jordi Quer (2001)

Journal de théorie des nombres de Bordeaux

Let C be a -curve with no complex multiplication. In this note we characterize the number fields K such that there is a curve C ' isogenous to C having all the isogenies between its Galois conjugates defined over K , and also the curves C ' isogenous to C defined over a number field K such that the abelian variety Res K / ( C ' / K ) obtained by restriction of scalars is a product of abelian varieties of GL 2 -type.

Fields of moduli of three-point G -covers with cyclic p -Sylow, II

Andrew Obus (2013)

Journal de Théorie des Nombres de Bordeaux

We continue the examination of the stable reduction and fields of moduli of G -Galois covers of the projective line over a complete discrete valuation field of mixed characteristic ( 0 , p ) , where G has a cyclic p -Sylow subgroup P of order p n . Suppose further that the normalizer of P acts on P via an involution. Under mild assumptions, if f : Y 1 is a three-point G -Galois cover defined over ¯ , then the n th higher ramification groups above p for the upper numbering of the (Galois closure of the) extension K / vanish,...

Fonction zêta d’Epstein et dilogarithme de Bloch-Wigner

Marie José Bertin (2011)

Journal de Théorie des Nombres de Bordeaux

Nous exprimons certaines séries d’Epstein normalisées en s = 2 comme combinaisons linéaires de dilogarithmes de Bloch-Wigner en des nombres algébriques des corps ( Δ ) pour les discriminants Δ associés à la forme quadratique.

Fonction zêta des hauteurs associée à une certaine surface cubique

Régis de la Bretèche, Peter Swinnerton-Dyer (2007)

Bulletin de la Société Mathématique de France

L’objet de cet article est d’obtenir une formule pour la fonction zêta des hauteurs classique à partir de la fonction zêta des hauteurs multiple de La Bretèche, et d’utiliser cette formule pour prolonger de manière méromorphe la fonction zêta des hauteurs. En particulier, il est montré que celle-ci peut être prolongée au demi-plan { s : e s > 3 4 } et que la frontière naturelle de son domaine naturel de méromorphie est { s : e s = 3 4 } .

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