Differential equations with 2-term recursion.
On étend une partie de la théorie de la structure de Frobenius faible des équations différentielles -adiques au cas où les coefficients sont des fonctions algébriques.
We shortly introduce non-archimedean valued fields and discuss the difficulties in the corresponding theory of analytic functions. We motivate the need of -adic cohomology with the Weil Conjectures. We review the two most popular approaches to -adic analytic varieties, namely rigid and Berkovich analytic geometries. We discuss the action of Frobenius in rigid cohomology as similar to the classical action of covering transformations. When rigid cohomology is parametrized by twisting characters,...
Dans cet article nous présentons la théorie des équations différentielles -adiques et ses applications concernant le théorème de finitude de la cohomologie -adique d’une variété affine et le théorème de la monodromie -adique des représentations galoisiennes locales.
Frobenius modules are difference modules with respect to a Frobenius operator. Here we show that over non-archimedean complete differential fields Frobenius modules define differential modules with the same Picard-Vessiot ring and the same Galois group schemes up to extension by constants. Moreover, these Frobenius modules are classified by unramified Galois representations over the base field. This leads among others to the solution of the inverse differential Galois problem for -adic differential...
Let be a -adic local field with residue field such that and be a -adic representation of . Then, by using the theory of -adic differential modules, we show that is a Hodge-Tate (resp. de Rham) representation of if and only if is a Hodge-Tate (resp. de Rham) representation of where is a certain -adic local field with residue field the smallest perfect field containing .
Nous désirons savoir si l’opérateur différentiel d’ordre , où est une matrice à coefficients rationnels, a un indice dans l’espace des fonctions analytiques dans une boule; dans le cas où cet indice existe nous voulons aussi le calculer. Dans le cas où nous montrons l’existence d’un indice (si l’exposant de l’opérateur n’est pas Liouville -adique) et nous montrons comment calculer cet indice. De même nous savons montrer l’existence d’un indice et comment calculer cet indice lorsque le système...
In this lecture we introduce the reader to the proof of the p-adic monodromy theorem linking the p-adic differential equations theory and the local Galois p-adic representations theory.
We study liftings or deformations of -modules ( is the ring of differential operators from EGA IV) from positive characteristic to characteristic zero using ideas of Matzat and Berthelot’s theory of arithmetic -modules. We pay special attention to the growth of the differential Galois group of the liftings. We also apply formal deformation theory (following Schlessinger and Mazur) to analyze the space of all liftings of a given -module in positive characteristic. At the end we compare the problems...