{"title":"Approximate identities for ideals in \n \n \n L\n (\n \n L\n p\n \n )\n \n $L(L^p)$","authors":"W. B. Johnson, G. Schechtman","doi":"10.1112/blms.13161","DOIUrl":null,"url":null,"abstract":"<p>The main result is that the only non-trivial closed ideal in the Banach algebra <span></span><math>\n <semantics>\n <mrow>\n <mi>L</mi>\n <mo>(</mo>\n <msup>\n <mi>L</mi>\n <mi>p</mi>\n </msup>\n <mo>)</mo>\n </mrow>\n <annotation>$L(L^p)$</annotation>\n </semantics></math> of bounded linear operators on <span></span><math>\n <semantics>\n <mrow>\n <msup>\n <mi>L</mi>\n <mi>p</mi>\n </msup>\n <mrow>\n <mo>(</mo>\n <mn>0</mn>\n <mo>,</mo>\n <mn>1</mn>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation>$L^p(0,1)$</annotation>\n </semantics></math>, <span></span><math>\n <semantics>\n <mrow>\n <mn>1</mn>\n <mo>⩽</mo>\n <mi>p</mi>\n <mo><</mo>\n <mi>∞</mi>\n </mrow>\n <annotation>$1\\leqslant p < \\infty$</annotation>\n </semantics></math>, that has a left approximate identity is the ideal of compact operators. The algebra <span></span><math>\n <semantics>\n <mrow>\n <mi>L</mi>\n <mo>(</mo>\n <msup>\n <mi>L</mi>\n <mn>1</mn>\n </msup>\n <mo>)</mo>\n </mrow>\n <annotation>$L(L^1)$</annotation>\n </semantics></math> has at least one non-trivial closed ideal that has a contractive right approximate identity as well as many, including the unique maximal ideal, that do not have a right approximate identity.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"56 12","pages":"3708-3720"},"PeriodicalIF":0.8000,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of the London Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1112/blms.13161","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
The main result is that the only non-trivial closed ideal in the Banach algebra of bounded linear operators on , , that has a left approximate identity is the ideal of compact operators. The algebra has at least one non-trivial closed ideal that has a contractive right approximate identity as well as many, including the unique maximal ideal, that do not have a right approximate identity.