Scaling in a map of the two-torus.
Simultaneous reduction to normal forms of commuting singular vector fields with linear parts having Jordan blocks
We study the simultaneous linearizability of –actions (and the corresponding -dimensional Lie algebras) defined by commuting singular vector fields in fixing the origin with nontrivial Jordan blocks in the linear parts. We prove the analytic convergence of the formal linearizing transformations under a certain invariant geometric condition for the spectrum of vector fields generating a Lie algebra. If the condition fails and if we consider the situation where small denominators occur, then...
Smooth Gevrey normal forms of vector fields near a fixed point
We study germs of smooth vector fields in a neighborhood of a fixed point having an hyperbolic linear part at this point. It is well known that the “small divisors” are invisible either for the smooth linearization or normal form problem. We prove that this is completely different in the smooth Gevrey category. We prove that a germ of smooth -Gevrey vector field with an hyperbolic linear part admits a smooth -Gevrey transformation to a smooth -Gevrey normal form. The Gevrey order depends on...
Solving the sextic by iteration: a study in complex geometry and dynamics.
Some counterexamples in dynamics of rational semigroups.
Some open problems in higher dimensional complex analysis and complex dynamics.
We present a collection of problems in complex analysis and complex dynamics in several variables.
Strong almost reducibility for analytic and Gevrey quasi-periodic cocycles
This article is about almost reducibility of quasi-periodic cocycles with a diophantine frequency which are sufficiently close to a constant. Generalizing previous works by L.H. Eliasson, we show a strong version of almost reducibility for analytic and Gevrey cocycles, that is to say, almost reducibility where the change of variables is in an analytic or Gevrey class which is independent of how close to a constant the initial cocycle is conjugated. This implies a result of density, or quasi-density,...
Structure of the McMullen domain in the parameter planes for rational maps
We show that, for the family of functions where n ≥ 3 and λ ∈ ℂ, there is a unique McMullen domain in parameter space. A McMullen domain is a region where the Julia set of is homeomorphic to a Cantor set of circles. We also prove that this McMullen domain is a simply connected region in the plane that is bounded by a simple closed curve.
Sur la dynamique arithmétique des automorphismes de l’espace affine
Nous étudions les propriétés arithmétiques des itérés de certains automorphismes polynomiaux affines. Nous traitons des questions concernant les points périodiques et non-périodiques, en particulier nous comptons les points rationnels dans les orbites des points non-périodiques. Nous traitons le cas des automorphismes réguliers et triangulaires. Nous achevons de répondre aux questions en dimension 2 et montrons que la situation est nettement plus compliquée en dimension supérieure.
Sur la persistance des courbes invariantes pour les dynamiques holomorphes fibrées lisses
En s’appuyant sur un théorème des fonctions implicites de Hamilton, nous montrons la persistance d’une courbe invariante indifférente pour une dynamique holomorphe fibrée de classe . Une condition diophantienne sur la paire de nombres de rotation est demandée. On montre également que cette condition est optimale.
Sur les ensembles de Julia et Fatou des fonctions entières ultramétriques
Soit un nombre premier rationnel. Le sujet de l’article est l’étude de la dynamique des fonctions entières -adiques. On démontre des résultats analogues à ceux connus dans le domaine complexe, en particulier si deux fonctions entières -adiques qui ont un point répulsif commun commutent, alors leurs ensembles de Julia et de Fatou sont les mêmes.
Sur une question de Bergweiler