Widom factors for the Hilbert norm
type: Item
instance of: scholarly article
title: Widom factors for the Hilbert norm
zbMATH Open document ID: 1342.42022
author: Gökalp Alpan
author: Alexander Goncharov
published in: Banach Center Publications
publication date: 2016-03-16T00:00:00Z
full work available at URL: http://hdl.handle.net/11693/48500
Mathematics Subject Classification ID: 42C05
Mathematics Subject Classification ID: 33C45
Mathematics Subject Classification ID: 30C85
Mathematics Subject Classification ID: 47B36
zbMATH DE Number: 6556699
zbMATH Keywords: orthogonal polynomials
zbMATH Keywords: Jacobi weight
zbMATH Keywords: Szegö class
zbMATH Keywords: Widom condition
zbMATH Keywords: Julia sets
MaRDI profile type: Publication
OpenAlex ID: W2579626443
DOI: 10.4064/BC107-0-1
review text: Let \(\mu\) be a probability Borel measure with compact support \(K\) on the complex plane and let (\(q_{n}\)) be the sequence of monic orthogonal polynomials with respect to \(\mu\). The \(n\)-th Widom-Hilbert factor of \(\mu\) is defined by NEWLINE\[NEWLINEW_{n}^{2}(\mu)=\frac{\|q_{n}\|_{L^{2}(\mu)}}{\mathrm{Cap}^{n}(K)},NEWLINE\]NEWLINE where \(\mathrm{Cap}(K)\) denotes the logarithmic capacity of \(K\).NEWLINENEWLINEIn the paper under review, the authors calculate \(\lim_{n\to\infty}W_{n}^{2}(\mu)\) for the measure \(\mu\) that generates the Jacobi polynomials, they examine the behavior of the Widom-Hilbert factors of the measure that generates the Pollaczek polynomials and of some irregular measures and they prove some extremal properties of the equilibrium measure of the interval \([-1,1]\) among the measures of the Szegö class. Also, they analyze the behavior of the Widom-Hilbert factors of the equilibrium measures of Julia sets.NEWLINENEWLINEFor the entire collection see [Zbl 1337.41001].
reviewed by: Stamatis Pouliasis
description: scientific article; zbMATH DE number 6556699