Several identities and inequalities involving Jordan closed curves.
Sobre la estabilización robusta para ciertos tipos de sistemas lineales.
In this paper we consider the problem of robust stabilization of systems with complex pole variations. We show that techniques from the complex function field can also be used to treat these cases. In particular the problem is reduced to one of interpolation theory on the disk.
Solution of a linear integral equation of third kind.
Solution of a spectral problem for the curl operator on a cylinder.
Solutions with prescribed periods on the boundary components on non-linear elliptic systems of first order in multiply connected domains in the plane
Solvability of a Riemann linear conjugation problem on a fractal surface.
Solving Complex Approximation Problems by Semiinfmite - Finite Optimization Techniques : A Study on Convergence.
Some applications of the theorem on rational approximation in the mean
Some Berezin number inequalities for operator matrices
Some properties of Van Koch's curves.
Some properties of weighted hyperbolic polynomials.
Some remarks on the space .
Some results on the Pompeiu problem.
Sommation effective d’une somme de Borel par séries de factorielles
Nous abordons dans cet article la question de la sommation effective d’une somme de Borel d’une série par la série de factorielles associée. Notre approche fournit un contrôle de l’erreur entre la somme de Borel recherchée et les sommes partielles de la série de factorielles. Nous généralisons ensuite cette méthode au cadre des séries de puissances fractionnaires, après avoir démontré un analogue d’un théorème de Nevanlinna de sommation de Borel fine pour ce cadre.
Spatial Riemann problem for analytic functions of two complex variables.
Spectral approximation for Segal-Bargmann space Toeplitz operators
Let A stand for a Toeplitz operator with a continuous symbol on the Bergman space of the polydisk or on the Segal-Bargmann space over . Even in the case N = 1, the spectrum Λ(A) of A is available only in a few very special situations. One approach to gaining information about this spectrum is based on replacing A by a large “finite section”, that is, by the compression of A to the linear span of the monomials . Unfortunately, in general the spectrum of does not mimic the spectrum of A as...
Spectral factorization of measurable rectangular matrix functions and the vector-valued Riemann problem.
We define spectral factorization in Lp (or a generalized Wiener-Hopf factorization) of a measurable singular matrix function on a simple closed rectifiable contour Γ. Such factorization has the same uniqueness properties as in the nonsingular case. We discuss basic properties of the vector valued Riemann problem whose coefficient takes singular values almost everywhere on Γ. In particular, we introduce defect numbers for this problem which agree with the usual defect numbers in the case of a nonsingular...
Spectral versus classical Nevanlinna-Pick interpolation in dimension two.
Stieltjes moment problem in general Gelfand-Shilov spaces
The Stieltjes moment problem is studied in the framework of general Gelfand-Shilov spaces, subspaces of the space of rapidly decreasing smooth complex functions, which are defined by imposing suitable bounds on their elements in terms of a given sequence M. Necessary and sufficient conditions on M are stated for the problem to have a solution, sometimes coming with linear continuous right inverses of the moment map, sending a function to the sequence of its moments. On the way, some results on the...
Stochastic continuity and approximation
This work is concerned with the study of stochastic processes which are continuous in probability, over various parameter spaces, from the point of view of approximation and extension. A stochastic version of the classical theorem of Mergelyan on polynomial approximation is shown to be valid for subsets of the plane whose boundaries are sets of rational approximation. In a similar vein, one can obtain a version in the context of continuity in probability of the theorem of Arakelyan on the uniform...