{"title":"将某些向量值函数空间表示为张量积","authors":"M. Abtahi","doi":"10.1007/s10476-023-0218-2","DOIUrl":null,"url":null,"abstract":"<div><p>Let <i>E</i> be a Banach space. For a topological space <i>X</i>, let <span>\\({{\\cal C}_b}(X,E)\\)</span> be the space of all bounded continuous <i>E</i>-valued functions on <i>X</i>, and let <span>\\({{\\cal C}_K}(X,E)\\)</span> be the subspace of <span>\\({{\\cal C}_b}(X,E)\\)</span> consisting of all functions having a pre-compact image in <i>E</i>. We show that <span>\\({{\\cal C}_K}(X,E)\\)</span> is isometrically isomorphic to the injective tensor product <span>\\({{\\cal C}_b}(X){{\\hat \\otimes}_\\varepsilon}E\\)</span>, and that <span>\\({{\\cal C}_b}(X,E) = {{\\cal C}_b}(X){{\\hat \\otimes}_\\varepsilon}E\\)</span> if and only if <i>E</i> is finite dimensional. Next, we consider the space Lip(<i>X, E</i>) of <i>E</i>-valued Lipschitz operators on a metric space (<i>X, d</i>) and its subspace Lip<sub><i>K</i></sub>(<i>X, E</i>) of Lipschitz compact operators. Utilizing the results on <span>\\({{\\cal C}_b}(X,E)\\)</span>, we prove that Lip<sub><i>K</i></sub>(<i>X, E</i>) is isometrically isomorphic to a tensor product <span>\\({\\rm{Lip}}(X){{\\hat \\otimes}_\\alpha}E\\)</span>, and that <span>\\({\\rm{Lip}}(X,E) = {\\rm{Lip}}(X){{\\hat \\otimes}_\\alpha}E\\)</span> if and only if <i>E</i> is finite dimensional. Finally, we consider the space <i>D</i><sup>1</sup>(<i>X, E</i>) of continuously differentiable functions on a perfect compact plane set <i>X</i> and show that, under certain conditions, <i>D</i><sup>1</sup>(<i>X, E</i>) is isometrically isomorphic to a tensor product <span>\\({D^1}(X){\\hat \\otimes _\\beta}E\\)</span>.</p></div>","PeriodicalId":55518,"journal":{"name":"Analysis Mathematica","volume":"49 2","pages":"337 - 353"},"PeriodicalIF":0.6000,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Representing certain vector-valued function spaces as tensor products\",\"authors\":\"M. Abtahi\",\"doi\":\"10.1007/s10476-023-0218-2\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Let <i>E</i> be a Banach space. For a topological space <i>X</i>, let <span>\\\\({{\\\\cal C}_b}(X,E)\\\\)</span> be the space of all bounded continuous <i>E</i>-valued functions on <i>X</i>, and let <span>\\\\({{\\\\cal C}_K}(X,E)\\\\)</span> be the subspace of <span>\\\\({{\\\\cal C}_b}(X,E)\\\\)</span> consisting of all functions having a pre-compact image in <i>E</i>. We show that <span>\\\\({{\\\\cal C}_K}(X,E)\\\\)</span> is isometrically isomorphic to the injective tensor product <span>\\\\({{\\\\cal C}_b}(X){{\\\\hat \\\\otimes}_\\\\varepsilon}E\\\\)</span>, and that <span>\\\\({{\\\\cal C}_b}(X,E) = {{\\\\cal C}_b}(X){{\\\\hat \\\\otimes}_\\\\varepsilon}E\\\\)</span> if and only if <i>E</i> is finite dimensional. Next, we consider the space Lip(<i>X, E</i>) of <i>E</i>-valued Lipschitz operators on a metric space (<i>X, d</i>) and its subspace Lip<sub><i>K</i></sub>(<i>X, E</i>) of Lipschitz compact operators. Utilizing the results on <span>\\\\({{\\\\cal C}_b}(X,E)\\\\)</span>, we prove that Lip<sub><i>K</i></sub>(<i>X, E</i>) is isometrically isomorphic to a tensor product <span>\\\\({\\\\rm{Lip}}(X){{\\\\hat \\\\otimes}_\\\\alpha}E\\\\)</span>, and that <span>\\\\({\\\\rm{Lip}}(X,E) = {\\\\rm{Lip}}(X){{\\\\hat \\\\otimes}_\\\\alpha}E\\\\)</span> if and only if <i>E</i> is finite dimensional. Finally, we consider the space <i>D</i><sup>1</sup>(<i>X, E</i>) of continuously differentiable functions on a perfect compact plane set <i>X</i> and show that, under certain conditions, <i>D</i><sup>1</sup>(<i>X, E</i>) is isometrically isomorphic to a tensor product <span>\\\\({D^1}(X){\\\\hat \\\\otimes _\\\\beta}E\\\\)</span>.</p></div>\",\"PeriodicalId\":55518,\"journal\":{\"name\":\"Analysis Mathematica\",\"volume\":\"49 2\",\"pages\":\"337 - 353\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2023-06-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Analysis Mathematica\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s10476-023-0218-2\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Analysis Mathematica","FirstCategoryId":"100","ListUrlMain":"https://link.springer.com/article/10.1007/s10476-023-0218-2","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
Representing certain vector-valued function spaces as tensor products
Let E be a Banach space. For a topological space X, let \({{\cal C}_b}(X,E)\) be the space of all bounded continuous E-valued functions on X, and let \({{\cal C}_K}(X,E)\) be the subspace of \({{\cal C}_b}(X,E)\) consisting of all functions having a pre-compact image in E. We show that \({{\cal C}_K}(X,E)\) is isometrically isomorphic to the injective tensor product \({{\cal C}_b}(X){{\hat \otimes}_\varepsilon}E\), and that \({{\cal C}_b}(X,E) = {{\cal C}_b}(X){{\hat \otimes}_\varepsilon}E\) if and only if E is finite dimensional. Next, we consider the space Lip(X, E) of E-valued Lipschitz operators on a metric space (X, d) and its subspace LipK(X, E) of Lipschitz compact operators. Utilizing the results on \({{\cal C}_b}(X,E)\), we prove that LipK(X, E) is isometrically isomorphic to a tensor product \({\rm{Lip}}(X){{\hat \otimes}_\alpha}E\), and that \({\rm{Lip}}(X,E) = {\rm{Lip}}(X){{\hat \otimes}_\alpha}E\) if and only if E is finite dimensional. Finally, we consider the space D1(X, E) of continuously differentiable functions on a perfect compact plane set X and show that, under certain conditions, D1(X, E) is isometrically isomorphic to a tensor product \({D^1}(X){\hat \otimes _\beta}E\).
期刊介绍:
Traditionally the emphasis of Analysis Mathematica is classical analysis, including real functions (MSC 2010: 26xx), measure and integration (28xx), functions of a complex variable (30xx), special functions (33xx), sequences, series, summability (40xx), approximations and expansions (41xx).
The scope also includes potential theory (31xx), several complex variables and analytic spaces (32xx), harmonic analysis on Euclidean spaces (42xx), abstract harmonic analysis (43xx).
The journal willingly considers papers in difference and functional equations (39xx), functional analysis (46xx), operator theory (47xx), analysis on topological groups and metric spaces, matrix analysis, discrete versions of topics in analysis, convex and geometric analysis and the interplay between geometry and analysis.