Search results for "J15"
showing 10 items of 22 documents
Normal forms of hyperbolic logarithmic transseries
2021
We find the normal forms of hyperbolic logarithmic transseries with respect to parabolic logarithmic normalizing changes of variables. We provide a necessary and sufficient condition on such transseries for the normal form to be linear. The normalizing transformations are obtained via fixed point theorems, and are given algorithmically, as limits of Picard sequences in appropriate topologies.
Vector-valued analytic functions of bounded mean oscillation and geometry of Banach spaces
1997
When dealing with vector-valued functions, sometimes is rather difficult to give non trivial examples, meaning examples which do not come from tensoring scalar-valued functions and vectors in the Banach space, belonging to certain classes. This is the situation for vector valued BMO. One of the objectives of this paper is to look for methods to produce such examples. Our main tool will be the vector-valued extension of the following result on multipliers, proved in [MP], which says that the space of multipliers between H and BMOA can be identified with the space of Bloch functions B, i.e. (H, BMOA) = B (see Section 3 for notation), which, in particular gives that g ∗ f ∈ BMOA whenever f ∈ H…
La maitrise du français écrit par les primo-arrivants : : une analyse des performances productives par frontière stochastique
2014
International audience; Cet article vise à déterminer les facteurs susceptibles d'expliquer le niveau de maîtrise du français écrit par les primo-arrivants en âge de travailler, sachant que peu de recherches ont été réalisées en France à ce sujet. L'originalité de cet article réside dans l'estimation d'une frontière stochastique de production afin d'expliquer les scores en français écrit des primo-arrivants (considérés comme producteurs de leurs propres compétences) et leurs performances productives. Les principaux résultats mettent en avant que la langue maternelle, l'âge au moment de l'immigration, le diplôme de la mère et la vie sociale sont des éléments qui influencent l'efficacité de c…
Same work, lower grade? Student ethnicity and teachers’ subjective assessments
2010
Previous research shows that ethnic minority students perform poorer in school when they are taught by ethnic majority teachers. Why this is the case was unclear. This paper focuses on one important potential explanation: I examine whether ethnic majority teachers grade minority and majority students differently for the same work. Using an experiment, I rule out the existence of such a direct grading bias. I do find indirect evidence for alternative explanations: teachers report lower expectations and unfavorable attitudes that both likely affect their behavior towards minority students, potentially inducing them to perform below their ability level. Effects of having majority teachers on m…
LES DISCRIMINATIONS A L'EMBAUCHE DANS LA SPHERE PUBLIQUE : EFFETS RESPECTIFS DE L'ADRESSE ET DE L'ORIGINE
2016
Cette étude évalue la discrimination dans l’accès à l’emploi dans trois professions présentes à la fois dans le secteur privé et dans la Fonction Publique. Deux dimensions sont examinées : l’effet de la réputation du lieu de résidence et l’effet de l’origine maghrébine. Elle est réalisée sur données expérimentales de testing réalisé dans trois professions en tension pour lesquelles la discrimination devrait a priori être très réduite : les responsables administratifs de catégorie A, les techniciens de maintenance de catégorie B et les aides soignantes de catégorie C. Pour chaque profession, nous avons construit 3 profils fictifs de candidats à l’emploi similaires en tout point à l’exception…
Determinants of inter-regional migration in the Baltic countries
2003
We show that Estonia, Latvia and Lithuania despite small geographical size feature considerable and persistent regional disparities. Registered migration rates have declined dramatically since the last years of Soviet era, yet they are high by international standards. Evidence from regional inflows and outflows in Latvia and from Estonian labour force survey is used to show that regional unemployment and especially wage differentials, as well as demographic factors, have a significant impact both on gross and net migration flows. Age and education effects are consistent with predictions of the human capital model of migration. Unemployed persons, as well as commuters between regions, are si…
Landis-type conjecture for the half-Laplacian
2023
In this paper, we study the Landis-type conjecture, i.e., unique continuation property from infinity, of the fractional Schrödinger equation with drift and potential terms. We show that if any solution of the equation decays at a certain exponential rate, then it must be trivial. The main ingredients of our proof are the Caffarelli-Silvestre extension and Armitage’s Liouville-type theorem. peerReviewed
A minimization problem with free boundary and its application to inverse scattering problems
2023
We study a minimization problem with free boundary, resulting in hybrid quadrature domains for the Helmholtz equation, as well as some application to inverse scattering problem.
Sub-Finsler Geodesics on the Cartan Group
2018
This paper is a continuation of the work by the same authors on the Cartan group equipped with the sub-Finsler $\ell_\infty$ norm. We start by giving a detailed presentation of the structure of bang-bang extremal trajectories. Then we prove upper bounds on the number of switchings on bang-bang minimizers. We prove that any normal extremal is either bang-bang, or singular, or mixed. Consequently, we study mixed extremals. In particular, we prove that every two points can be connected by a piecewise smooth minimizer, and we give a uniform bound on the number of such pieces.
Gleason parts for algebras of holomorphic functions on the ball of $\mathbf{c_0}$
2019
For a complex Banach space $X$ with open unit ball $B_X,$ consider the Banach algebras $\mathcal H^\infty(B_X)$ of bounded scalar-valued holomorphic functions and the subalgebra $\mathcal A_u(B_X)$ of uniformly continuous functions on $B_X.$ Denoting either algebra by $\mathcal A,$ we study the Gleason parts of the set of scalar-valued homomorphisms $\mathcal M(\mathcal A)$ on $\mathcal A.$ Following remarks on the general situation, we focus on the case $X = c_0.$