{"title":"非交换支盖和束单可化性","authors":"Alexandru Chirvasitu","doi":"arxiv-2409.03531","DOIUrl":null,"url":null,"abstract":"We prove that (a) the sections space of a continuous unital subhomogeneous\n$C^*$ bundle over compact metrizable $X$ admits a finite-index expectation onto\n$C(X)$, answering a question of Blanchard-Gogi\\'{c} (in the metrizable case);\n(b) such expectations cannot, generally, have ``optimal index'', answering\nnegatively a variant of the same question; and (c) a homogeneous continuous\nBanach bundle over a locally paracompact base space $X$ can be renormed into a\nHilbert bundle in such a manner that the original space of bounded sections is\n$C_b(X)$-linearly Banach-Mazur-close to the resulting Hilbert module over the\nalgebra $C_b(X)$ of continuous bounded functions on $X$. This last result\nresolves quantitatively another problem posed by Gogi\\'{c}.","PeriodicalId":501114,"journal":{"name":"arXiv - MATH - Operator Algebras","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Non-commutative branched covers and bundle unitarizability\",\"authors\":\"Alexandru Chirvasitu\",\"doi\":\"arxiv-2409.03531\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We prove that (a) the sections space of a continuous unital subhomogeneous\\n$C^*$ bundle over compact metrizable $X$ admits a finite-index expectation onto\\n$C(X)$, answering a question of Blanchard-Gogi\\\\'{c} (in the metrizable case);\\n(b) such expectations cannot, generally, have ``optimal index'', answering\\nnegatively a variant of the same question; and (c) a homogeneous continuous\\nBanach bundle over a locally paracompact base space $X$ can be renormed into a\\nHilbert bundle in such a manner that the original space of bounded sections is\\n$C_b(X)$-linearly Banach-Mazur-close to the resulting Hilbert module over the\\nalgebra $C_b(X)$ of continuous bounded functions on $X$. This last result\\nresolves quantitatively another problem posed by Gogi\\\\'{c}.\",\"PeriodicalId\":501114,\"journal\":{\"name\":\"arXiv - MATH - Operator Algebras\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-09-05\",\"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-2409.03531\",\"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-2409.03531","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Non-commutative branched covers and bundle unitarizability
We prove that (a) the sections space of a continuous unital subhomogeneous
$C^*$ bundle over compact metrizable $X$ admits a finite-index expectation onto
$C(X)$, answering a question of Blanchard-Gogi\'{c} (in the metrizable case);
(b) such expectations cannot, generally, have ``optimal index'', answering
negatively a variant of the same question; and (c) a homogeneous continuous
Banach bundle over a locally paracompact base space $X$ can be renormed into a
Hilbert bundle in such a manner that the original space of bounded sections is
$C_b(X)$-linearly Banach-Mazur-close to the resulting Hilbert module over the
algebra $C_b(X)$ of continuous bounded functions on $X$. This last result
resolves quantitatively another problem posed by Gogi\'{c}.