Une remarque sur les idéaux de fonctions différentiables

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Périodicité des fractions continues dans un corps de fonctions hyperelliptiques

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Racines cubiques de nombres entiers et multiplication complexe dans les fonctions elliptiques

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Équations aux différences dans les vecteurs de Witt

We prove an approximation property for Frobenius difference equations in the Witt vectors, analog to a theorem of Greenberg [Publ. Math. IHES 31 (1966) 59–64]. To cite this article: L. Bélair, C. R. Acad. Sci. Paris, Ser. I 340 (2005).     

Idéaux fermés d'algèbres de Beurling analytiques sur le bidisque

We study the closed ideal in the Beurling algebras of holomorphic function f in the bidisc such that

     

Sur la formule de Jensen et les zeros des fonctions holomorphes dans le polydisque

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Croissance du nombre de classes dans desZ l -extensions liées aux corps quadratiques imaginaires

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Filtration de certains espaces de fonctions sur un espace symétrique réductif

We introduce a filtration of a -module of some space of functions on a reductive symmetric space G/H, and compute the associated grading as a direct sum of induced representations. As an application of this result to the reductive groups viewed as symmetric spaces, we are able to realize any Harish-Chandra module as a subquotient of a direct sum of induced representations from parabolic subgroups, the inducing representations being trivial on the unipotent radical.     

Correspondance de Jacquet-Langlands pour les corps locaux de caractéristique non nulle

In this article we prove the Jacquet-Langlands local correspondence in non-zero characteristic. Let F be a local field of non-zero charactersitic and G′ an inner form of GL_n(F); then, following [17], we prove relations between the representation theory of G′ and the representation theory of an inner form of GL_n(L), where L is a local field of zero characteristic close to F. The proof of the Jacquet-Langlands correspondence between G′ and GL_n(F) is done using the above results and ideas from the proof by Deligne, Kazhdan and Vignéras [10] of the zero characteristic case. We also get the following, already known in zero characteristic: orthogonality relations for G′, inequality involving conductor and level for representations of G′ and finiteness for automorphic cuspidal representations with fixed component at almost every place for an inner form of GL_n over a global field of non-zero characteristic.     

Sur les fonctions q-Bessel de Jackson

(About Jackson q-Bessel functions)Laplace transform allows to resolve differential equations in the neighborhood of an irregular singular point. The purpose of the article is to study how to apply a basic Borel–Laplace transformation to q-difference equations satisfied by the q-Bessel functions of F.H. Jackson. Connection matrices are obtained between solutions at the origin and solutions at infinity.     

Hauteurs de sous-espaces sur les corps non commutatifs

We study heights of subspaces of D ^N where D is a finite-dimensional rational division algebra and N a positive integer. We define them in terms of volumes of Euclidean lattices by extending a formula of W. Schmidt so that we recover the classical height if D is commutative. We review basic properties, prove a Siegel Lemma over D, a duality theorem and a new formula for the degree of certain abelian varieties. We further give matrix versions and compare our notion with the height defined through algebraic groups by J. Franke, Y. Manin and Y. Tschinkel.      

Une compactification des champs classifiant les chtoucas de Drinfeld

One knows that the notion of Harder-Narasimhan's canonical polygon allows one to write the stacks classifying Drinfeld's shtukas of rank at least as inductive limits of open substacks of finite type. When there is no level structure, we present here a smooth modular compactification of each such open substack, generalizing Drinfeld's construction for rank .

Résumé. On sait qu'en rang au moins , la notion de polygone canonique de Harder-Narasimhan permet d'écrire les champs classifiant les chtoucas de Drinfeld comme des réunions filtrantes d'ouverts de type fini. Quand il n'y a pas de structure de niveau, on présente ici une compactification modulaire lisse de chacun de ces ouverts, généralisant celles de Drinfeld en rang .

     

Sur les distributions covariantes dans les algèbres de Lie réductives

We study the possibility of factoring a covariant distribution on reductive Lie algebras as finite sum of products of an invariant distribution by a covariant polynomial.     

Élimination des quantificateurs dans les équations aux différences linéaires sur les vecteurs de Witt

We prove quantifier elimination in Witt vectors over an algebraically closed fields (or in power series), considered as a valued module over the Ore ring of Frobenius polynomials. We get that these structures do not have the independence property. To cite this article: L. Bélair, F. Point, C. R. Acad. Sci. Paris, Ser. I 346 (2008).     

Dihedral side extensions and class groups

We present a non-abelian mirror-type principle relating the p-ranks of class groups of subfields of a dihedral field of degree 2p for an odd prime p with a limited ramification condition.     

Fonctions rationnelles aux différences à valeurs entières dans les vecteurs de Witt

We transpose Kochen's results on integral valued rational functions over the p-adic numbers to difference rational functions over the Witt vectors with their Frobenius. To cite this article: L. Bélair, C. R. Acad. Sci. Paris, Ser. I 339 (2004).