Using the techniques developed by Jean Ecalle for the study of nonlinear differential equations, we prove that the -difference equationwith () and is analytically conjugated to one of the following equations :
In this paper we introduce a new invariant for extensions of difference fields, the distant degree, and discuss its properties.
In ultrametric Nevanlinna theory, the Nevanlinna’s second main theorem for small functions has only been proved in the case of at most three small functions. In this paper, we prove a second main theorem for small functions of a special type when the residue characteristic of the field is zero.
Un algorithme est présenté pour calculer en toute généralité le « réseau de Levelt » pour un réseau donné.
We generalize and unify the proofs of several results on algebraic independence of arithmetic functions and Dirichlet series by using a theorem of Ax on the differential Schanuel conjecture. Along the way, we find counter-examples to some results in the literature.
We survey recent work on arithmetic analogues of ordinary and partial differential equations.
Dans ce travail nous développons un analogue relatif de la théorie de Sen pour les -représentations. On donne des applications à la théorie des représentations -adiques, en la reliant à la théorie des -modules relatifs, et à celle des modules de Higgs -adiques développée par G. Faltings.
The differential automorphism group, over F, Π₁(F₁) of the Picard-Vessiot closure F₁ of a differential field F is a proalgebraic group over the field of constants of F, which is assumed to be algebraically closed of characteristic zero, and its category of modules is equivalent to the category of differential modules over F. We show how this group and the category equivalence behave under a differential extension E ⊃ F, where is also algebraically closed.
One of the classical Bernstein inequalities compares the maxima of a polynomial of a given degree on the interval [-1,1] and on the ellipse in the complex plane with the focuses -1, 1 and the semiaxes . We prove a similar inequality for a branch of an algebraic function of a given degree on the maximal disk of its regularity, with the explicitly given constant, depending on the degree only. In particular, this improves a recent inequality of Fefferman and Narasimhan and answers one of their questions....
Border bases are an alternative to Gröbner bases. The former have several more desirable properties. In this paper some constructions and operations on border bases are presented. Namely; the case of a restriction of an ideal to a polynomial ring (in a smaller number of variables), the case of the intersection of two ideals, and the case of the kernel of a homomorphism of polynomial rings. These constructions are applied to the ideal of relations and to factorizable derivations.
Dans cet article, nous démontrons une inégalité liant la croissance d’un casoratien généralisé de séries entières -adique à la croissance du casoratien ordinaire de ces séries entières. Il en résulte que si le casoratien de fonctions entières -adiques est un polynôme non nul, alors toutes ces fonctions sont des polynômes. Comme application, nous montrons que si une équation aux différences linéaire d’ordre à coefficients dans a solutions méromorphes dans tout , linéairement indépendantes...