{"title":"On an Extremal Problem for Compactly Supported Positive Definite Functions","authors":"A. D. Manov","doi":"10.1134/S1064562424701965","DOIUrl":null,"url":null,"abstract":"<p>An extremal problem for positive definite functions on <span>\\({{\\mathbb{R}}^{n}}\\)</span> with a fixed support and a fixed value at the origin (the class <span>\\({{\\mathfrak{F}}_{r}}({{\\mathbb{R}}^{n}})\\)</span>) is considered. It is required to find the least upper bound for a special form functional over <span>\\({{\\mathfrak{F}}_{r}}({{\\mathbb{R}}^{n}})\\)</span>. This problem is a generalization of the Turán problem for functions with support in a ball. A general solution to this problem for <span>\\(n \\ne 2\\)</span> is obtained. As a consequence, new sharp inequalities are obtained for derivatives of entire functions of exponential spherical type.</p>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://link.springer.com/article/10.1134/S1064562424701965","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
An extremal problem for positive definite functions on \({{\mathbb{R}}^{n}}\) with a fixed support and a fixed value at the origin (the class \({{\mathfrak{F}}_{r}}({{\mathbb{R}}^{n}})\)) is considered. It is required to find the least upper bound for a special form functional over \({{\mathfrak{F}}_{r}}({{\mathbb{R}}^{n}})\). This problem is a generalization of the Turán problem for functions with support in a ball. A general solution to this problem for \(n \ne 2\) is obtained. As a consequence, new sharp inequalities are obtained for derivatives of entire functions of exponential spherical type.