{"title":"希尔伯特 $C^*$ 模块中的非紧密性度量","authors":"Dragoljub J. Kečkić, Zlatko Lazović","doi":"arxiv-2409.02514","DOIUrl":null,"url":null,"abstract":"Consider a countably generated Hilbert $C^*$-module $\\mathcal M$ over a\n$C^*$-algebra $\\mathcal A$. There is a measure of noncompactness $\\lambda$\ndefined, roughly as the distance from finitely generated projective submodules,\nwhich is independent of any topology. We compare $\\lambda$ to the Hausdorff\nmeasure of noncompactness with respect to the family of seminorms that induce a\ntopology recently iontroduced by Troitsky, denoted by $\\chi^*$. We obtain\n$\\lambda\\equiv\\chi^*$. Related inequalities involving other known measures of\nnoncompactness, e.g. Kuratowski and Istr\\u{a}\\c{t}escu are laso obtained as\nwell as some related results on adjontable operators.","PeriodicalId":501114,"journal":{"name":"arXiv - MATH - Operator Algebras","volume":"23 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Measures of noncompactness in Hilbert $C^*$-modules\",\"authors\":\"Dragoljub J. Kečkić, Zlatko Lazović\",\"doi\":\"arxiv-2409.02514\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Consider a countably generated Hilbert $C^*$-module $\\\\mathcal M$ over a\\n$C^*$-algebra $\\\\mathcal A$. There is a measure of noncompactness $\\\\lambda$\\ndefined, roughly as the distance from finitely generated projective submodules,\\nwhich is independent of any topology. We compare $\\\\lambda$ to the Hausdorff\\nmeasure of noncompactness with respect to the family of seminorms that induce a\\ntopology recently iontroduced by Troitsky, denoted by $\\\\chi^*$. We obtain\\n$\\\\lambda\\\\equiv\\\\chi^*$. Related inequalities involving other known measures of\\nnoncompactness, e.g. Kuratowski and Istr\\\\u{a}\\\\c{t}escu are laso obtained as\\nwell as some related results on adjontable operators.\",\"PeriodicalId\":501114,\"journal\":{\"name\":\"arXiv - MATH - Operator Algebras\",\"volume\":\"23 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-09-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - MATH - Operator Algebras\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2409.02514\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - MATH - Operator Algebras","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.02514","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Measures of noncompactness in Hilbert $C^*$-modules
Consider a countably generated Hilbert $C^*$-module $\mathcal M$ over a
$C^*$-algebra $\mathcal A$. There is a measure of noncompactness $\lambda$
defined, roughly as the distance from finitely generated projective submodules,
which is independent of any topology. We compare $\lambda$ to the Hausdorff
measure of noncompactness with respect to the family of seminorms that induce a
topology recently iontroduced by Troitsky, denoted by $\chi^*$. We obtain
$\lambda\equiv\chi^*$. Related inequalities involving other known measures of
noncompactness, e.g. Kuratowski and Istr\u{a}\c{t}escu are laso obtained as
well as some related results on adjontable operators.