Formule d'homotopie pour un domaine à bord (q+k)-concave d'une variété CR générique et q-concave. Applications

Salomon Sambou; Bocar Touré

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Displaying similar documents to “Formule d'homotopie pour un domaine à bord (q+k)-concave d'une variété CR générique et q-concave. Applications”

Sur les courbes hyperelliptiques cyclotomiques et les équations $x^{p} - y^{p} = c z ²$

Wilfrid Ivorra

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Let p be a prime number ≥ 11 and c be a square-free integer ≥ 3. In this paper, we study the diophantine equation $x^{p} - y^{p} = c z ²$ in the case where p belongs to 11,13,17. More precisely, we prove that for those primes, there is no integer solution (x,y,z) to this equation satisfying gcd(x,y,z) = 1 and xyz ≠ 0 if the integer c has the following property: if ℓ is a prime number dividing c then ℓ ≢ 1 mod p. To obtain this result, we consider the hyperelliptic curves $C_{p} : y ² = Φ_{p} (x)$ and $D_{p} : p y ² = Φ_{p} (x)$ , where $Φ_{p}$ is the pth cyclotomic...

Idéaux fermés de certaines algèbres de Beurling et application aux opérateurs à spectre dénombrable

Cyril Agrafeuil (2005)

Studia Mathematica

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We denote by the unit circle and by the unit disc of ℂ. Let s be a non-negative real and ω a weight such that $ω (n) = {(1 + n)}^{s}$ (n ≥ 0) and the sequence ${(ω (- n) / {(1 + n)}^{s})}_{n \geq 0}$ is non-decreasing. We define the Banach algebra $A_{ω} () = {f \in () : | | f | |}_{ω} = \sum_{n = - \infty}^{+ \infty} | f ̂ (n) | ω (n) < + \infty$ . If I is a closed ideal of $A_{ω} ()$ , we set $h ⁰ (I) = z \in : f (z) = 0 (f \in I)$ . We describe all closed ideals I of $A_{ω} ()$ such that h⁰(I) is at most countable. A similar result is obtained for closed ideals of the algebra $A ⁺_{s} () = f \in A_{ω} () : f ̂ (n) = 0 (n < 0)$ without inner factor. Then we use this description to establish a link between operators with countable spectrum and interpolating...

Sur un problème de Rényi et Ivić concernant les fonctions de diviseurs de Piltz

Rimer Zurita (2013)

Acta Arithmetica

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Let Ω(n) and ω(n) denote the number of distinct prime factors of the positive integer n, counted respectively with and without multiplicity. Let $d_{k} (n)$ denote the Piltz function (which counts the number of ways of writing n as a product of k factors). We obtain a precise estimate of the sum $\sum_{n \leq x, Ω (n) - ω (n) = q} f (n)$ for a class of multiplicative functions f, including in particular $f (n) = d_{k} (n)$ , unconditionally if 1 ≤ k ≤ 3, and under some reasonable assumptions if k ≥ 4. The result also applies to f(n) = φ(n)/n (where φ is...

Fonctions maximales centrées de Hardy-Littlewood sur les groupes de Heisenberg

Hong-Quan Li (2009)

Studia Mathematica

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By getting uniformly asymptotic estimates for the Poisson kernel on Heisenberg groups $ℍ_{2 n + 1}$ , we prove that there exists a constant A > 0, independent of n ∈ ℕ*, such that for all $f \in L ¹ (ℍ_{2 n + 1})$ , we have ${| | M f | |}_{L^{1, \infty}} \leq A n | | f | | ₁$ , where M denotes the centered Hardy-Littlewood maximal function defined by the Carnot-Carathéodory distance or by the Korányi norm.

Une formule pour les extensions de foncteurs composés

Alain Troesch (2003)

Fundamenta Mathematicae

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Let p be a prime, and let ℱ be the category of functors from the finite $_{p}$ -vector spaces to all $_{p}$ -vector spaces. The object Id of ℱ is the inclusion functor. Let F and G be two objects in ℱ. If F and G satisfy suitable conditions, the main result of this paper allows one to compute $E x t *_{ℱ} (I d, G \circ F)$ from the knowledge of $E x t *_{ℱ} (I d, F)$ and $E x t *_{ℱ} (I d, G)$ .

Présentation jordanienne de l'algèbre de Weyl A₂

J. Alev, F. Dumas (2001)

Annales Polonici Mathematici

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Let k be a commutative field. For any a,b∈ k, we denote by $J_{a, b} (k)$ the deformation of the 2-dimensional Weyl algebra over k associated with the Jordanian Hecke symmetry with parameters a and b. We prove that: (i) any $J_{a, b} (k)$ can be embedded in the usual Weyl algebra A₂(k), and (ii) $J_{a, b} (k)$ is isomorphic to A₂(k) if and only if a = b.

Inégalités à poids pour l'opérateur de Hardy-Littlewood-Sobolev dans les espaces métriques mesurés à deux demi-dimensions

David Mascré (2006)

Colloquium Mathematicae

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On a metric measure space (X,ϱ,μ), consider the weight functions $w_{α} (x) = ϱ {(x, z ₀)}^{- α ₀}$ if ϱ(x,z₀) < 1, $w_{α} (x) = ϱ {(x, z ₀)}^{- α ₁}$ if ϱ(x,z₀) ≥ 1, $w_{β} (x) = ϱ {(x, z ₀)}^{- β ₀}$ if ϱ(x,z₀) < 1, $w_{β} (x) = ϱ {(x, z ₀)}^{- β ₁}$ if ϱ(x,z₀) ≥ 1, where z₀ is a given point of X, and let $κ_{a} : X \times X \to ℝ ₊$ be an operator kernel satisfying $κ_{a} (x, y) \leq c ϱ {(x, y)}^{a - d}$ for all x,y ∈ X such that ϱ(x,y) < 1, $κ_{a} (x, y) \leq c ϱ {(x, y)}^{a - D}$ for all x,y ∈ X such that ϱ(x,y)≥ 1, where 0 < a < min(d,D), and d and D are respectively the local and global volume growth rate of the space X. We determine conditions on a, α₀, α₁, β₀, β₁ ∈ ℝ for the Hardy-Littlewood-Sobolev...

Derivees tangentielles des fonctions de la classe $^{k, α}$ dans les domaines de type fini de ℂ²

Laurent Verdoucq (2002)

Annales Polonici Mathematici

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Let Ω be a domain of finite type in ℂ² and let f be a function holomorphic in Ω and belonging to $^{k, α} (Ω ̅)$ . We prove the existence of boundary values for some suitable derivatives of f of order greater than k. The gain of derivatives holds in the complex-tangential direction and it is precisely related to the geometry of ∂Ω. Then we prove a property of non-isotropic Hölder regularity for these boundary values. This generalizes some results given by J. Bruna and J. M. Ortega for the unit ball. ...

Espaces BMO, inégalités de Paley et multiplicateurs idempotents

Hubert Lelièvre (1997)

Studia Mathematica

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Generalizing the classical BMO spaces defined on the unit circle with vector or scalar values, we define the spaces $B M O_{ψ_{q}} ()$ and $B M O_{ψ_{q}} (, B)$ , where $ψ_{q} (x) = e^{x^{q}} - 1$ for x ≥ 0 and q ∈ [1,∞[, and where B is a Banach space. Note that $B M O_{ψ_{1}} () = B M O ()$ and $B M O_{ψ_{1}} (, B) = B M O (, B)$ by the John-Nirenberg theorem. Firstly, we study a generalization of the classical Paley inequality and improve the Blasco-Pełczyński theorem in the vector case. Secondly, we compute the idempotent multipliers of $B M O_{ψ_{q}} ()$ . Pisier conjectured that the supports of idempotent multipliers of...

Sur un problème parabolique-elliptique

Philippe Benilan, Petra Wittbold (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

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We prove existence (uniqueness is easy) of a weak solution to a boundary value problem for an equation like ${(v - 1)}_{t}^{+} = v_{x x} + F {(v)}_{x}$ where the function $F : ℝ \to ℝ$ is only supposed to be locally lipschitz continuous. In order to replace the lack of compactness in on , we use nonlinear semigroup theory.

Feuilletages holomorphes de codimension un dont la classe canonique est triviale

Frédéric Touzet (2008)

Annales scientifiques de l'École Normale Supérieure

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We give a description of Kähler manifolds $M$ equipped with an integrable subbundle $ℱ$ of $T M$ of rank $n - 1$ ( $n = \dim M$ ) under the assumption that the line bundle $D é t ℱ$ is numerically trivial. This is a sort of foliated version of Bogomolov’s theorem concerning Kähler manifolds with trivial canonical class.

Les -types du système $ℱ$

K. Nour (2010)

RAIRO - Theoretical Informatics and Applications

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We prove in this paper that the types of system $ℱ$ inhabited uniquely by λ-terms (the -types) have a positive quantifier. We give also consequences of this result and some examples.

Problème de Plateau complexe dans les variétés kählériennes

Frédéric Sarkis (2002)

Bulletin de la Société Mathématique de France

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L’étude du « problème de Plateau complexe » (ou « problème du bord ») dans une variété complexe $X$ consiste à caractériser les sous-variétés réelles $Γ$ de $X$ qui sont le bord de sous-ensembles analytiques de $X ∖ Γ$ . Notre principal résultat traite le cas $X = U \times ω$ où $U$ est une variété complexe connexe et $ω$ est une variété kählérienne disque convexe. Comme conséquence, nous obtenons des résultats de Harvey-Lawson [19], Dolbeault-Henkin [12] et Dinh [10]. Nous obtenons aussi une généralisation des théorèmes...

$L^{p} (G, X )$ comme sous-espace complémenté de $L^{q} (G, X) $

Mohammad Daher (2013)

Colloquium Mathematicae

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Let G be a compact metric infinite abelian group and let X be a Banach space. We study the following question: if the dual X* of X does not have the Radon-Nikodym property, is $L^{p} (G, X *)$ complemented in $L^{q} (G, X) *$ , 1 < p ≤ ∞, 1/p + 1/q = 1, or, if p = 1, in the subspace of C(G,X)* consisting of the measures that are absolutely continuous with respect to the Haar measure? We show that the answer is negative if X is separable and does not contain ℓ¹, and if 1 ≤ p < ∞. If p = 1, this answers a question...

Stabilité $L^{1}$ d’ondes progressives de lois de conservation scalaires

Denis Serre (1998-1999)

Séminaire Équations aux dérivées partielles

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A powerfull method has been developped in [2] for the study of $L^{1}$ -stability of travelling waves in conservation laws or more generally in equations which display $L^{1}$ -contractivity, maximum principle and mass conservation. We recall shortly the general procedure. We also show that it partly applies to the waves of a model of radiating gas. These waves have first been studied by Kawashima and Nishibata [5,6] in a different framework. Therefore, shock fronts for this model are stable under...

Éléments de distorsion de ${Diff}_{0}^{\infty} (M)$

Emmanuel Militon (2013)

Bulletin de la Société Mathématique de France

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Dans cet article, on montre que, dans le groupe ${Diff}_{0}^{\infty} (M)$ des difféomorphismes isotopes à l’identité d’une variété compacte $M$ , tout élément récurrent est de distorsion. Pour ce faire, on généralise une méthode de démonstration utilisée par Avila pour le cas de ${Diff}_{0}^{\infty} (𝕊^{1})$ . La méthode nous permet de retrouver un résultat de Calegari et Freedman selon lequel tout homéomorphisme de la sphère isotope à l’identité est un élément de distorsion.

Variétés de codimension $2$ dans $P^{n}$

L. Szpiro (1972)

Publications mathématiques et informatique de Rennes

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Sur la classification des séries discrètes des groupes classiques p-adiques: paramètres de Langlands et exhaustivité

Colette Moeglin (2002)

Journal of the European Mathematical Society

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In this paper, we are giving parameters for discrete series of classical $p$ -adic groups. We first define: the analogous of the Langlands morphism of $W_{F}$ in the $L$ -group, part of the analogous of the character of the centralizer of that morphism and, to supply the missing part of the full definition of that character, the cuspidal support of the representation. Then, we state an hypothesis on the reducibility points for induced of cuspidal representations. And we prove that, under this hypothesis,...

Sur les variétés $X \subset ℙ^{N}$ telles que par $n$ points passe une courbe de $X$ de degré donné

Luc Pirio, Jean-Marie Trépreau (2013)

Bulletin de la Société Mathématique de France

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Soit $r \geq 1$ , $n \geq 2$ , et $q \geq n - 1$ des entiers. On introduit la classe $𝒳_{r + 1, n} (q)$ des sous-variétés $X$ de dimension $r + 1$ d’un espace projectif, telles que pour $(x_{1}, ..., x_{n}) \in X^{n}$ générique, il existe une courbe rationnelle normale de degré $q$ , contenue dans $X$ et passant par les points $x_{1}, ..., x_{n}$ ; $X$ engendre un espace projectif dont la dimension, pour $r$ , $n$ et $q$ donnés, est la plus grande possible compte tenu de la première propriété. Sous l’hypothèse $q \neq 2 n - 3$ , on détermine toutes les variétés $X$ appartenant à la classe $𝒳_{r + 1, n} (q)$ . On montre en particulier qu’il...

Minoration du spectre des variétés hyperboliques de dimension 3

Pierre Jammes (2012)

Bulletin de la Société Mathématique de France

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Soit $M$ une variété hyperbolique compacte de dimension 3, de diamètre $d$ et de volume $\leq V$ . Si on note $μ_{i} (M)$ la $i$ -ième valeur propre du laplacien de Hodge-de Rham agissant sur les 1-formes coexactes de $M$ , on montre que $μ_{1} (M) \geq \frac{c}{d^{3} e^{2 k d}}$ et $μ_{k + 1} (M) \geq \frac{c}{d^{2}}$ , où $c > 0$ est une constante ne dépendant que de $V$ , et $k$ est le nombre de composantes connexes de la partie mince de $M$ . En outre, on montre que pour toute 3-variété hyperbolique $M_{\infty}$ de volume fini avec cusps, il existe une suite $M_{i}$ de remplissages compacts de $M_{\infty}$ , de diamètre $d_{i} \to + \infty$ telle...

Ground states of supersymmetric matrix models

Gian Michele Graf (1998-1999)

Séminaire Équations aux dérivées partielles

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We consider supersymmetric matrix Hamiltonians. The existence of a zero-energy bound state, in particular for the $d = 9$ model, is of interest in M-theory. While we do not quite prove its existence, we show that the decay at infinity such a state would have is compatible with normalizability (and hence existence) in $d = 9$ . Moreover, it would be unique. Other values of $d$ , where the situation is somewhat different, shall also be addressed. The analysis is based on a Born-Oppenheimer approximation....