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Substitutions par des motifs en dimension 1

N. Pytheas Fogg (2007)

RAIRO - Theoretical Informatics and Applications

Une substitution est un morphisme de monoïdes libres : chaque lettre a pour image un mot, et l'image d'un mot est la concaténation des images de ses lettres. Cet article introduit une généralisation de la notion de substitution, où l'image d'une lettre n'est plus un mot mais un motif, c'est-à-dire un “mot à trous”, l'image d'un mot étant obtenue en raccordant les motifs correspondant à chacune de ses lettres à l'aide de règles locales. On caractérise complètement les substitutions par des motifs...

Suites doubles de basse complexité

Valérie Berthé, Laurent Vuillon (2000)

Journal de théorie des nombres de Bordeaux

Nous donnons une représentation géométrique des suites doubles uniformément récurrentes de fonction de complexité rectangulaire m n + n . Nous montrons que ces suites codent l’action d’une ℤ 2 -action définie par deux rotations irrationnelles sur le cercle unité. La preuve repose sur une étude des suites doubles dont les lignes sont des suite sturmiennes de même langage.

Sulla stabilità di un punto fisso per funzioni di n variabili complesse. Problema del Centro di Schröder-Siegel

Timoteo Carletti (2005)

Bollettino dell'Unione Matematica Italiana

Viene considerato il problema della stabilità di un punto fisso per un germe di diffeomorfismo di più variabili complesse cercando un coniugio con la sua parte lineare: Problema del centro di Schröder-Siegel. Dopo aver formulato il problema e ricordato i principali risultati nel caso di diffeomorfismi olomorfi, mostriamo come estendere il problema ad alcune situazioni non olomorfe, in particolare ci interesseremo al caso di germi Gevrey. Concluderemo con un'applicazione rivolta a mostrare la stabilità...

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.

S-unimodal Misiurewicz maps with flat critical points

Roland Zweimüller (2004)

Fundamenta Mathematicae

We consider S-unimodal Misiurewicz maps T with a flat critical point c and show that they exhibit ergodic properties analogous to those of interval maps with indifferent fixed (or periodic) points. Specifically, there is a conservative ergodic absolutely continuous σ-finite invariant measure μ, exact up to finite rotations, and in the infinite measure case the system is pointwise dual ergodic with many uniform and Darling-Kac sets. Determining the order of return distributions to suitable reference...

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...

Superintegrable Potentials and superposition of Higgs Oscillators on the Sphere S²

Manuel F. Rañada, Teresa Sanz-Gil, Mariano Santander (2003)

Banach Center Publications

The spherical version of the two-dimensional central harmonic oscillator, as well as the spherical Kepler (Schrödinger) potential, are superintegrable systems with quadratic constants of motion. They belong to two different spherical "Smorodinski-Winternitz" families of superintegrable potentials. A new superintegrable oscillator have been recently found in S². It represents the spherical version of the nonisotropic 2:1 oscillator and it also belongs to a spherical family of quadratic superintegrable...

Support overlapping L 1 contractions and exact non-singular transformations

Michael Lin (2000)

Colloquium Mathematicae

Let T be a positive linear contraction of L 1 of a σ-finite measure space (X,Σ,μ) which overlaps supports. In general, T need not be completely mixing, but it is in the following cases: (i) T is the Frobenius-Perron operator of a non-singular transformation ϕ (in which case complete mixing is equivalent to exactness of ϕ). (ii) T is a Harris recurrent operator. (iii) T is a convolution operator on a compact group. (iv) T is a convolution operator on a LCA group.

Sur la cohomologie dans les schémas de Bernoulli

Thierry de la Rue (2000)

Colloquium Mathematicae

We introduce an invariant of cohomology in Bernoulli shifts, which is used to answer a question about cohomology of Hölder functions with finitary functions whose coding time is integrable. When restricted to the class of Hölder functions, this invariant even provides a criterion of cohomology.

Sur la construction de mesures selles

Henry de Thélin (2006)

Annales de l’institut Fourier

Nous construisons des mesures selles (dans un sens faible) pour les endomorphismes holomorphes de ℙ 2 ( ℂ ) .

Sur la convergence faible des systèmes dynamiques échantillonnés

Nadine Guillotin-Plantard (2004)

Annales de l’institut Fourier

Soit T α la rotation sur le cercle d’angle irrationnel α , soit ( S k ) k ≥ 0 une marche aléatoire transiente sur ℤ . Soit f ∈ L 2 ( μ ) et H ∈ ] 0 , 1 [ , nous étudions la convergence faible de la suite 1 n H ∑ k = 0 [ n t ] - 1 f ∘ T α S k , n ≥ 1 .

Sur la densité des systèmes de Pfaff sans solution algébrique

Luis G. Mendes, Marcos Sebastiani (1994)

Annales de l'institut Fourier

On démontre que dans toute surface rationnelle, non-isomorphe au plan projectif, il existe une feuilletage analytique rigide, possédant des feuilles algébriques et n’ayant que des singularités isolées.

Currently displaying 361 – 380 of 490