A local-global criterion for dynamics on ℙ¹
Abelian varieties, ...-adic representations, and ...-independence.
Algebraic covers : field of moduli versus field of definition
Algebraic leaves of algebraic foliations over number fields
We prove an algebraicity criterion for leaves of algebraic foliations defined over number fields. Namely, consider a number field embedded in , a smooth algebraic variety over , equipped with a rational point , and an algebraic subbundle of the its tangent bundle , defined over . Assume moreover that the vector bundle is involutive, i.e., closed under Lie bracket. Then it defines an holomorphic foliation of the analytic manifold , and one may consider its leaf through . We prove...
An explicit version of Birch's Theorem
Arithmetic hyperbolic surface bundles.
Arithmetic of 0-cycles on varieties defined over number fields
Let be a rationally connected algebraic variety, defined over a number field We find a relation between the arithmetic of rational points on and the arithmetic of zero-cycles. More precisely, we consider the following statements: (1) the Brauer-Manin obstruction is the only obstruction to weak approximation for -rational points on for all finite extensions (2) the Brauer-Manin obstruction is the only obstruction to weak approximation in some sense that we define for zero-cycles of degree...
Bicyclotomic polynomials and impossible intersections
In a recent paper we proved that there are at most finitely many complex numbers such that the points and are both torsion on the Legendre elliptic curve defined by . In a sequel we gave a generalization to any two points with coordinates algebraic over the field and even over . Here we reconsider the special case and with complex numbers and .
Capacity theory on varieties
Comptage de courbes sur le plan projectif éclaté en trois points alignés
Nous établissons une version de la conjecture de Manin pour le plan projectif éclaté en trois points alignés, le corps de base étant un corps global de caractéristique positive.
Contre-exemples au principe de Hasse pour certains tores coflasques
Nous étudions le comportement asymptotique du nombre de variétés dans une certaine classe ne satisfaisant pas le principe de Hasse. Cette étude repose sur des résultats récemment obtenus par Colliot-Thélène [3].
Corps de définition et points rationnels
Soit un objet algébrique (par exemple une courbe ou un revêtement) défini sur et de corps des modules un corps de nombres . Il est bien connu que n’admet pas nécessairement de -modèle. En utilisant deux résultats récents dus à P. Dèbes, J.-C. Douai et M. Emsalem nous donnerons un majorant pour le degré d’un corps de définition de sur . Dans une deuxième partie, nous donnerons des conditions suffisantes sur l’ordre de Aut() pour que admette un -modèle.
Corrigendum - Points entiers et théorèmes de Bertini arithmétiques
Counting points of fixed degree and bounded height
Counting rational points on cubic and quartic surfaces
Counting rational points on del Pezzo surfaces with a conic bundle structure
For any number field k, upper bounds are established for the number of k-rational points of bounded height on non-singular del Pezzo surfaces defined over k, which are equipped with suitable conic bundle structures over k.
Counting rational points on hypersurfaces of low dimension
Cycles, L-functions and triple products of elliptic curves.
Density of rational points on elliptic fibrations-II
Des obstructions globales à la descente des revêtements