{"title":"赋范线性空间中弱紧集的凸性","authors":"I.G. Tsar’kov","doi":"10.1134/S1061920825600539","DOIUrl":null,"url":null,"abstract":"<p> We study weakly compact subsets of normed linear spaces admitting, for each <span>\\(\\varepsilon>0\\)</span>, an <i>nw</i>-continuous <span>\\(\\varepsilon\\)</span>-selection and such that the closure of their convex hull is weakly compact in this space. Such sets are shown to be convex. An application of this result to the linear manifold of all analytic functions in <span>\\(L_1\\)</span> is given. </p><p> <b> DOI</b> 10.1134/S1061920825600539 </p>","PeriodicalId":763,"journal":{"name":"Russian Journal of Mathematical Physics","volume":"32 3","pages":"585 - 589"},"PeriodicalIF":1.5000,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Convexity of Weakly Compact Sets in Normed Linear Spaces\",\"authors\":\"I.G. Tsar’kov\",\"doi\":\"10.1134/S1061920825600539\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p> We study weakly compact subsets of normed linear spaces admitting, for each <span>\\\\(\\\\varepsilon>0\\\\)</span>, an <i>nw</i>-continuous <span>\\\\(\\\\varepsilon\\\\)</span>-selection and such that the closure of their convex hull is weakly compact in this space. Such sets are shown to be convex. An application of this result to the linear manifold of all analytic functions in <span>\\\\(L_1\\\\)</span> is given. </p><p> <b> DOI</b> 10.1134/S1061920825600539 </p>\",\"PeriodicalId\":763,\"journal\":{\"name\":\"Russian Journal of Mathematical Physics\",\"volume\":\"32 3\",\"pages\":\"585 - 589\"},\"PeriodicalIF\":1.5000,\"publicationDate\":\"2025-09-29\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Russian Journal of Mathematical Physics\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://link.springer.com/article/10.1134/S1061920825600539\",\"RegionNum\":3,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"PHYSICS, MATHEMATICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Russian Journal of Mathematical Physics","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1134/S1061920825600539","RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PHYSICS, MATHEMATICAL","Score":null,"Total":0}
Convexity of Weakly Compact Sets in Normed Linear Spaces
We study weakly compact subsets of normed linear spaces admitting, for each \(\varepsilon>0\), an nw-continuous \(\varepsilon\)-selection and such that the closure of their convex hull is weakly compact in this space. Such sets are shown to be convex. An application of this result to the linear manifold of all analytic functions in \(L_1\) is given.
期刊介绍:
Russian Journal of Mathematical Physics is a peer-reviewed periodical that deals with the full range of topics subsumed by that discipline, which lies at the foundation of much of contemporary science. Thus, in addition to mathematical physics per se, the journal coverage includes, but is not limited to, functional analysis, linear and nonlinear partial differential equations, algebras, quantization, quantum field theory, modern differential and algebraic geometry and topology, representations of Lie groups, calculus of variations, asymptotic methods, random process theory, dynamical systems, and control theory.