{"title":"Trace and Extension Theorems for Homogeneous Sobolev and Besov Spaces for Unbounded Uniform Domains in Metric Measure Spaces","authors":"Ryan Gibara, Nageswari Shanmugalingam","doi":"10.1134/s0081543823050061","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> In this paper we fix <span>\\(1\\le p<\\infty\\)</span> and consider <span>\\((\\Omega,d,\\mu)\\)</span> to be an unbounded, locally compact, non-complete metric measure space equipped with a doubling measure <span>\\(\\mu\\)</span> supporting a <span>\\(p\\)</span>-Poincaré inequality such that <span>\\(\\Omega\\)</span> is a uniform domain in its completion <span>\\(\\overline\\Omega\\)</span>. We realize the trace of functions in the Dirichlet–Sobolev space <span>\\(D^{1,p}(\\Omega)\\)</span> on the boundary <span>\\(\\partial\\Omega\\)</span> as functions in the homogeneous Besov space <span>\\(H\\kern-1pt B^\\alpha_{p,p}(\\partial\\Omega)\\)</span> for suitable <span>\\(\\alpha\\)</span>; here, <span>\\(\\partial\\Omega\\)</span> is equipped with a non-atomic Borel regular measure <span>\\(\\nu\\)</span>. We show that if <span>\\(\\nu\\)</span> satisfies a <span>\\(\\theta\\)</span>-codimensional condition with respect to <span>\\(\\mu\\)</span> for some <span>\\(0<\\theta<p\\)</span>, then there is a bounded linear trace operator <span>\\(T \\colon\\, D^{1,p}(\\Omega)\\to H\\kern-1pt B^{1-\\theta/p}(\\partial\\Omega)\\)</span> and a bounded linear extension operator <span>\\(E \\colon\\, H\\kern-1pt B^{1-\\theta/p}(\\partial\\Omega)\\to D^{1,p}(\\Omega)\\)</span> that is a right-inverse of <span>\\(T\\)</span>. </p>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1134/s0081543823050061","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
In this paper we fix \(1\le p<\infty\) and consider \((\Omega,d,\mu)\) to be an unbounded, locally compact, non-complete metric measure space equipped with a doubling measure \(\mu\) supporting a \(p\)-Poincaré inequality such that \(\Omega\) is a uniform domain in its completion \(\overline\Omega\). We realize the trace of functions in the Dirichlet–Sobolev space \(D^{1,p}(\Omega)\) on the boundary \(\partial\Omega\) as functions in the homogeneous Besov space \(H\kern-1pt B^\alpha_{p,p}(\partial\Omega)\) for suitable \(\alpha\); here, \(\partial\Omega\) is equipped with a non-atomic Borel regular measure \(\nu\). We show that if \(\nu\) satisfies a \(\theta\)-codimensional condition with respect to \(\mu\) for some \(0<\theta<p\), then there is a bounded linear trace operator \(T \colon\, D^{1,p}(\Omega)\to H\kern-1pt B^{1-\theta/p}(\partial\Omega)\) and a bounded linear extension operator \(E \colon\, H\kern-1pt B^{1-\theta/p}(\partial\Omega)\to D^{1,p}(\Omega)\) that is a right-inverse of \(T\).
Abstract In this paper we fix\(1\le p<\infty\) and consider \((\Omega,d,\mu)\) to be an unbounded, locally compact, non-complete metric measure space equipped with a doubling measure \(\mu\) supporting a \(p\)-Poincaré inequality such that \(\Omega\) is a uniform domain in its completion \(\overline\Omega\).我们将边界 \(\partial\Omega\) 上的 Dirichlet-Sobolev 空间 \(D^{1,p}(\Omega)\) 中的函数的迹作为同质 Besov 空间 \(H\kern-1pt B^\alpha_{p,p}(\partial\Omega)\) 中的函数来实现,对于合适的 \(\alpha\);这里,\(\partial\Omega\) 配备了一个非原子的波尔正则量度\(\nu\)。我们证明,如果\(\nu\)满足一个关于\(\mu\)的\(\theta\)-codimensional条件,对于某个\(0<\theta<;p),那么存在一个有界线性迹算子(T \colon\, D^{1,p}(\Omega)\to H\kern-1pt B^{1-\theta/p}(\partial\Omega)\) 和一个有界线性扩展算子(E \colon\、H\kern-1pt B^{1-\theta/p}(\partial\Omega)\to D^{1,p}(\Omega)\) 是 \(T\)的右逆。