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Stability of higher order singular points of Poisson manifolds and Lie algebroids

Jean-Paul Dufour, Aïssa Wade (2006)

Annales de l’institut Fourier

We study the stability of singular points for smooth Poisson structures as well as general Lie algebroids. We give sufficient conditions for stability lying on the first-order approximation (not necessarily linear) of a given Poisson structure or Lie algebroid at a singular point. The main tools used here are the classical Lichnerowicz-Poisson cohomology and the deformation cohomology for Lie algebroids recently introduced by Crainic and Moerdijk. We also provide several examples of stable singular...

Stable norms of non-orientable surfaces

Florent Balacheff, Daniel Massart (2008)

Annales de l’institut Fourier

We study the stable norm on the first homology of a closed non-orientable surface equipped with a Riemannian metric. We prove that in every conformal class there exists a metric whose stable norm is polyhedral. Furthermore the stable norm is never strictly convex if the first Betti number of the surface is greater than two.

Strong almost reducibility for analytic and Gevrey quasi-periodic cocycles

Claire Chavaudret (2013)

Bulletin de la Société Mathématique de France

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,...

Structures symplectiques singulières génériques

Spyros N. Pnevmatikos (1984)

Annales de l'institut Fourier

Soit M une variété différentiable de dimension paire munie d’une 2-forme différentielle fermée générique Ω . L’apparition éventuelle d’un lieu de dégénérescence Σ ( Ω ) du rang de Ω est l’obstacle à ce que ( M , Ω ) soit une structure symplectique. Nous étudions les propriétés géométriques de Σ ( Ω ) et nous caractérisons l’algèbre des hamiltoniennes admissibles de ( M , Ω ) i.e. les fonctions différentiables h qui possèdent un champ hamiltonien X h sur M .

Subharmonic solutions of a nonconvex noncoercive hamiltonian system

Najeh Kallel, Mohsen Timoumi (2004)

RAIRO - Operations Research - Recherche Opérationnelle

In this paper we study the existence of subharmonic solutions of the hamiltonian system J x ˙ + u * G ( t , u ( x ) ) = e ( t ) where u is a linear map, G is a C 1 -function and e is a continuous function.

Summability of first integrals of a C ω -non-integrable resonant Hamiltonian system

Masafumi Yoshino (2012)

Banach Center Publications

This article studies the summability of first integrals of a C ω -non-integrable resonant Hamiltonian system. The first integrals are expressed in terms of formal exponential transseries and their Borel sums. Smooth Liouville integrability and a relation to the Birkhoff transformation are discussed from the point of view of the summability.

Superintegrability and time-dependent integrals

Ondřej Kubů, Libor Šnobl (2019)

Archivum Mathematicum

While looking for additional integrals of motion of several minimally superintegrable systems in static electric and magnetic fields, we have realized that in some cases Lie point symmetries of Euler-Lagrange equations imply existence of explicitly time-dependent integrals of motion through Noether’s theorem. These integrals can be combined to get an additional time-independent integral for some values of the parameters of the considered systems, thus implying maximal superintegrability. Even for...

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