{"title":"无 Lipschitz 空间和近似投影序列","authors":"Gilles Godefroy","doi":"10.1007/s43037-024-00332-2","DOIUrl":null,"url":null,"abstract":"<p>The Lipschitz-free space <span>\\({\\mathcal {F}}(M)\\)</span> has an F.D.D. when <i>M</i> is a separable <span>\\({\\mathcal {L}}_1\\)</span>-Banach space, or when <span>\\(M\\subset {\\mathbb {R}}^n\\)</span> is a somewhat regular subset. The interplay between the existence of extension operators for Lipschitz maps and the <span>\\((\\pi )\\)</span>-property in Lipschitz-free spaces is investigated. If <i>M</i> is an arbitrary metric space, then <span>\\({\\mathcal {F}}(M)\\)</span> has the <span>\\((\\pi )\\)</span>-property up to a universal logarithmic factor. It follows in particular that the <span>\\((\\pi )\\)</span>-property up to a logarithmic factor fails to imply the approximation property. A list of commented open problems is provided.</p>","PeriodicalId":55400,"journal":{"name":"Banach Journal of Mathematical Analysis","volume":null,"pages":null},"PeriodicalIF":1.1000,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Lipschitz-free spaces and approximating sequences of projections\",\"authors\":\"Gilles Godefroy\",\"doi\":\"10.1007/s43037-024-00332-2\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>The Lipschitz-free space <span>\\\\({\\\\mathcal {F}}(M)\\\\)</span> has an F.D.D. when <i>M</i> is a separable <span>\\\\({\\\\mathcal {L}}_1\\\\)</span>-Banach space, or when <span>\\\\(M\\\\subset {\\\\mathbb {R}}^n\\\\)</span> is a somewhat regular subset. The interplay between the existence of extension operators for Lipschitz maps and the <span>\\\\((\\\\pi )\\\\)</span>-property in Lipschitz-free spaces is investigated. If <i>M</i> is an arbitrary metric space, then <span>\\\\({\\\\mathcal {F}}(M)\\\\)</span> has the <span>\\\\((\\\\pi )\\\\)</span>-property up to a universal logarithmic factor. It follows in particular that the <span>\\\\((\\\\pi )\\\\)</span>-property up to a logarithmic factor fails to imply the approximation property. A list of commented open problems is provided.</p>\",\"PeriodicalId\":55400,\"journal\":{\"name\":\"Banach Journal of Mathematical Analysis\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.1000,\"publicationDate\":\"2024-03-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Banach Journal of Mathematical Analysis\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1007/s43037-024-00332-2\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Banach Journal of Mathematical Analysis","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s43037-024-00332-2","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
Lipschitz-free spaces and approximating sequences of projections
The Lipschitz-free space \({\mathcal {F}}(M)\) has an F.D.D. when M is a separable \({\mathcal {L}}_1\)-Banach space, or when \(M\subset {\mathbb {R}}^n\) is a somewhat regular subset. The interplay between the existence of extension operators for Lipschitz maps and the \((\pi )\)-property in Lipschitz-free spaces is investigated. If M is an arbitrary metric space, then \({\mathcal {F}}(M)\) has the \((\pi )\)-property up to a universal logarithmic factor. It follows in particular that the \((\pi )\)-property up to a logarithmic factor fails to imply the approximation property. A list of commented open problems is provided.
期刊介绍:
The Banach Journal of Mathematical Analysis (Banach J. Math. Anal.) is published by Birkhäuser on behalf of the Tusi Mathematical Research Group.
Banach J. Math. Anal. is a peer-reviewed electronic journal publishing papers of high standards with deep results, new ideas, profound impact, and significant implications in all areas of functional analysis and operator theory and all modern related topics. Banach J. Math. Anal. normally publishes survey articles and original research papers numbering 15 pages or more in the journal’s style. Shorter papers may be submitted to the Annals of Functional Analysis or Advances in Operator Theory.