derniers depôts

Ajouté le 27/06/2019

A novel enantiopure bis-helicenic 2,2'-bipyridine system was prepared using a Negishi coupling. Thanks to the bipyridine unit, the coordination with ZnII and protonation processes were studied revealing efficient tuning of photophysical (UV/Visible and emission) and chiroptical properties (electronic circular dichroism and circularly polarized emission) of the system.

Ajouté le 25/06/2019

We continue the investigation of which non-dierentiable maps can occur in the framework of ergodic theory started in [2]. We construct a Besicovitch-Morse function map which preserves the Lebesgue measure. We also show that the set of Besicovitch functions is of rst category in the set of continuous functions which preserve the Lebesgue measure.

Ajouté le 22/06/2019

Recent works on simplified clarinet models using results from dynamic bifurcation theory have allowed to predict the evolution of the amplitude of sound (the amplitude envelope) for a gradual increase of the blowing pressure. The unrealistic model that predicted the amplitudes to attain very small values, far below the precision of a computer, was later corrected by the addition of stochastic noise to the model.

Ajouté le 20/06/2019

For $Q$ a polynomial with integer coefficients and $x, y \geq 2$, we prove upper bounds for the quantity $\Psi_Q(x, y) = |\{n\leq x: p\mid Q(n)\Rightarrow p\leq y\}|$. We apply our results to a problem of De Koninck, Doyon and Luca on integers divisible by the square of their largest prime factor. As a corollary to our arguments, we improve the known level of distribution of the set $\{n^2-D\}$ for well-factorable moduli, previously due to Iwaniec.

Ajouté le 21/06/2019

Nous proposons une analyse critique de l’ensemble des exercices de l’épreuve de mathématiques 2017 du brevet ayant trait au thème « Algorithmique et programmation » du programme de cycle 4. Certains de ces exercices ne mettent en jeu que de manière très superficielle des compétences spécifiquement informatiques, mais portent plutôt sur des compétences mathématiques « traditionnelles », liées par exemple à l’algèbre ou la géométrie.

Ajouté le 20/06/2019

This paper provides rates of convergence for empirical (generalised) barycenters on compact geodesic metric spaces under general conditions using empirical processes techniques. Our main assumption is termed a variance inequality and provides a strong connection between usual assumptions in the field of empirical processes and central concepts of metric geometry. We study the validity of variance inequalities in spaces of non-positive and non-negative Aleksandrov curvature.

Ajouté le 19/06/2019

We prove that the Stern diatomic sequence is asymptotically distributed according to a normal law, on a logarithmic scale. This is obtained by studying complex moments, and the analytic properties of a transfer operator.

Ajouté le 19/06/2019

Ce travail a pour but de mieux comprendre les mécanismes perceptifs et cognitifs mis en œuvre lors de l'écoute des sons, et en particulier, d'´étudier les relations entre les traitements cognitifs associés à la sémantique dans le langage et à la sémiotique des objets sonores (i.e. comment attribue-t-on un sens au son). Il vise également à mieux cerner les relations entre la structure acoustique des sons et l'information perceptive et cognitive qu'ils véhiculent.

Ajouté le 19/06/2019

We show that automatic sequences are asymptotically orthogonal to periodic exponentials of type $e_q(f(n))$, where $f$ is a rational fraction, in the P\'olya-Vinogradov range. This applies to Kloosterman sums, and may be used to study solubility of congruence equations over automatic sequences. We obtain this as consequence of a general result, stating that sums over automatic sequences can be bounded effectively in terms of two-point correlation sums over intervals.