arXiv subjects

Elie Mosaki

Publications and source records attributed to Elie Mosaki.

5 recordsLinked to original sources

arXiv2013

Sur la complexité de familles d'ensembles pseudo-aléatoires

In this paper we are interested in the following problem. Let $p$ be a prime number, $S\subset \F_p$ and $\cP\subset \{P\in\F_p [X]:°P\le d\}$. What is the largest integer $k$ such that for all subsets $\cA, \cB$ of $\F_p$ satisfying $\cA\cap\cB =\emptyset$ and $|\cA\cup\cB |=k$, there exists $P\in\cP$ such that $P(x)\in S$ if $x\in\cA$ and $P(x)\not\in S$ if $x\in\cB$? This problem corresponds to the study of the complexity of some families of pseudo-random subsets. First we recall this complexity definition and the context of pseudo-random subsets. Then we state the different results we have obtained according to the shape of the sets $S$ and $\cP$ considered. Some proofs are based on upper bounds for exponential sums or characters sums in finite fields, other proofs use combinatorics and additive number theory.

math.NT↗

arXiv2011

Zero-free regions for Dirichlet series (II)

In this paper, we continue some work devoted to explicit zero-free discs for a large class of Dirichlet series. In a previous article, such zero-free regions were described using some spaces of functions which were defined with some technical conditions. Here we give two different natural ways in order to remove those technical conditions. In particular this allows to right down explicit zero-free regions differently and to obtain for them an easier description useful for direct applications.

math.FA↗

arXiv2011

Zero free regions for Dirichlet series

In this paper, we are interested in explicit zero-free discs for some Dirichlet series and we also study a general Beurling-Nyman criterion for $L$-functions. Our results generalize and improve previous results obtained by N. Nikolski and by A. de Roton. As a concrete application, we get, for example, a Beurling-Nyman type criterion for the Siegel zero problem.

math.NT↗

arXiv2008

Diophantine properties for q-analogues of Dirichlet's beta function at positive integers

small In this paper, we define $q$-analogues of Dirichlet's beta function at positive integers, which can be written as $β_q(s)=\sum_{k\geq1}\sum_{d|k}χ(k/d)d^{s-1}q^k$ for $s\in\N^*$, where $q$ is a complex number such that $|q|<1$ and $χ$ is the non trivial Dirichlet character modulo 4. For odd $s$, these expressions are connected with the automorphic world, in particular with Eisenstein series of level 4. From this, we derive through Nesterenko's work the transcendance of the numbers $β_q(2s+1)$ for $q$ algebraic such that $0<|q|<1$. Our main result concerns the nature of the numbers $β_q(2s)$: we give a lower bound for the dimension of the vector space over $\Q$ spanned by $1,β_q(2),β_q(4),...,β_q(A)$, where $1/q\in\Z\setminus\{-1;1\}$ and $A$ is an even integer. As consequences, for $1/q\in\Z\setminus\{-1;1\}$, on the one hand there is an infinity of irrational numbers among $β_q(2),β_q(4),...$, and on the other hand at least one of the numbers $β_q(2),β_q(4),..., β_q(20)$ is irrational.

math.NT↗

arXiv2007

Irrationalité aux entiers impairs positifs d'un q-analogue de la fonction zeta de Riemann

In this paper, we focus on a q-analogue of the Riemann zeta function at positive integers, which can be written for s\in\N^* by ζ_q(s)=\sum_{k\geq 1}q^k\sum_{d|k}d^{s-1}. We give a new lower bound for the dimension of the vector space over \Q spanned, for 1/q\in\Z\setminus\{-1;1\} and an even integer A, by 1,ζ_q(3),ζ_q(5),...,ζ_q(A-1). This improves a recent result of Krattenthaler, Rivoal and Zudilin (\emph{Séries hypergéométriques basiques, q-analogues des valeurs de la fonction zeta et séries d'Eisenstein}, J. Inst. Jussieu {\bf 5}.1 (2006), 53-79). In particular, a consequence of our result is that for 1/q\in\Z\setminus\{-1;1\}, at least one of the numbers ζ_q(3),ζ_q(5),ζ_q(7),ζ_q(9) is irrational.

math.CO↗