{ "id": "1403.6927", "version": "v2", "published": "2014-03-27T06:43:55.000Z", "updated": "2014-03-28T00:50:32.000Z", "title": "On a Theorem by Bojanov and Naidenov applied to families of Gegenbauer-Sobolev polynomials", "authors": [ "Vanessa G. Paschoa", "Dilcia Pérez", "Yamilet Quintana" ], "comment": "2 figures", "categories": [ "math.CA" ], "abstract": "Let $\\{Q^{(\\alpha)}_{n,\\lambda}\\}_{n\\geq 0}$ be the sequence of monic orthogonal polynomials with respect the Gegenbauer-Sobolev inner product $$\\langle f,g\\rangle_{S}:=\\int_{-1}^{1}f(x)g(x)(1-x^{2})^{\\alpha-\\frac{1}{2}}dx+\\lambda \\int_{-1}^{1}f'(x)g'(x)(1-x^{2})^{\\alpha-\\frac{1}{2}} dx,$$ where $\\alpha>-\\frac{1}{2}$ and $\\lambda\\geq 0$. In this paper we use a recent result due to B.D. Bojanov and N. Naidenov \\cite{BN2010}, in order to study the maximization of a local extremum of the $k$th derivative $\\frac{d^k}{dx^k}Q^{(\\alpha)}_{n,\\lambda}$ in $[-M_{n,\\lambda}, M_{n,\\lambda}]$, where $M_{n,\\lambda}$ is a suitable value such that all zeros of the polynomial $Q^{(\\alpha)}_{n,\\lambda}$ are contained in $[-M_{n,\\lambda}, M_{n,\\lambda}]$ and the function $\\left|Q^{(\\alpha)}_{n,\\lambda}\\right|$ attains its maximal value at the end-points of such interval. Also, some illustrative numerical examples are presented.", "revisions": [ { "version": "v2", "updated": "2014-03-28T00:50:32.000Z" } ], "analyses": { "subjects": [ "33C45", "41A17" ], "keywords": [ "gegenbauer-sobolev polynomials", "monic orthogonal polynomials", "gegenbauer-sobolev inner product", "local extremum" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1403.6927P" } } }