{"title":"原始理想空间上的连续动作提升到C * $\\ mathm {C}^\\ast$ -actions","authors":"Matteo Pagliero","doi":"10.1112/blms.13203","DOIUrl":null,"url":null,"abstract":"<p>We prove that for any second-countable, locally compact group <span></span><math>\n <semantics>\n <mi>G</mi>\n <annotation>$G$</annotation>\n </semantics></math>, any continuous <span></span><math>\n <semantics>\n <mi>G</mi>\n <annotation>$G$</annotation>\n </semantics></math>-action on the primitive ideal space of a separable, nuclear <span></span><math>\n <semantics>\n <msup>\n <mi>C</mi>\n <mo>*</mo>\n </msup>\n <annotation>$\\mathrm{C}^\\ast$</annotation>\n </semantics></math>-algebra <span></span><math>\n <semantics>\n <mi>B</mi>\n <annotation>$B$</annotation>\n </semantics></math> such that <span></span><math>\n <semantics>\n <mrow>\n <mi>B</mi>\n <mo>≅</mo>\n <mi>B</mi>\n <mo>⊗</mo>\n <msub>\n <mi>O</mi>\n <mn>2</mn>\n </msub>\n <mo>⊗</mo>\n <mi>K</mi>\n </mrow>\n <annotation>$B \\cong B\\otimes \\mathcal {O}_2\\otimes \\mathcal {K}$</annotation>\n </semantics></math> is induced by an action on <span></span><math>\n <semantics>\n <mi>B</mi>\n <annotation>$B$</annotation>\n </semantics></math>. As a direct consequence, we establish that every continuous action on the primitive ideal space of a separable, nuclear <span></span><math>\n <semantics>\n <msup>\n <mi>C</mi>\n <mo>*</mo>\n </msup>\n <annotation>$\\mathrm{C}^\\ast$</annotation>\n </semantics></math>-algebra is induced by an action on a <span></span><math>\n <semantics>\n <msup>\n <mi>C</mi>\n <mo>*</mo>\n </msup>\n <annotation>$\\mathrm{C}^\\ast$</annotation>\n </semantics></math>-algebra with the same primitive ideal space. Moreover, we discuss an application to the classification of equivariantly <span></span><math>\n <semantics>\n <msub>\n <mi>O</mi>\n <mn>2</mn>\n </msub>\n <annotation>$\\mathcal {O}_2$</annotation>\n </semantics></math>-stable actions.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 2","pages":"404-425"},"PeriodicalIF":1.0000,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Continuous actions on primitive ideal spaces lift to \\n \\n \\n C\\n *\\n \\n $\\\\mathrm{C}^\\\\ast$\\n -actions\",\"authors\":\"Matteo Pagliero\",\"doi\":\"10.1112/blms.13203\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We prove that for any second-countable, locally compact group <span></span><math>\\n <semantics>\\n <mi>G</mi>\\n <annotation>$G$</annotation>\\n </semantics></math>, any continuous <span></span><math>\\n <semantics>\\n <mi>G</mi>\\n <annotation>$G$</annotation>\\n </semantics></math>-action on the primitive ideal space of a separable, nuclear <span></span><math>\\n <semantics>\\n <msup>\\n <mi>C</mi>\\n <mo>*</mo>\\n </msup>\\n <annotation>$\\\\mathrm{C}^\\\\ast$</annotation>\\n </semantics></math>-algebra <span></span><math>\\n <semantics>\\n <mi>B</mi>\\n <annotation>$B$</annotation>\\n </semantics></math> such that <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>B</mi>\\n <mo>≅</mo>\\n <mi>B</mi>\\n <mo>⊗</mo>\\n <msub>\\n <mi>O</mi>\\n <mn>2</mn>\\n </msub>\\n <mo>⊗</mo>\\n <mi>K</mi>\\n </mrow>\\n <annotation>$B \\\\cong B\\\\otimes \\\\mathcal {O}_2\\\\otimes \\\\mathcal {K}$</annotation>\\n </semantics></math> is induced by an action on <span></span><math>\\n <semantics>\\n <mi>B</mi>\\n <annotation>$B$</annotation>\\n </semantics></math>. As a direct consequence, we establish that every continuous action on the primitive ideal space of a separable, nuclear <span></span><math>\\n <semantics>\\n <msup>\\n <mi>C</mi>\\n <mo>*</mo>\\n </msup>\\n <annotation>$\\\\mathrm{C}^\\\\ast$</annotation>\\n </semantics></math>-algebra is induced by an action on a <span></span><math>\\n <semantics>\\n <msup>\\n <mi>C</mi>\\n <mo>*</mo>\\n </msup>\\n <annotation>$\\\\mathrm{C}^\\\\ast$</annotation>\\n </semantics></math>-algebra with the same primitive ideal space. Moreover, we discuss an application to the classification of equivariantly <span></span><math>\\n <semantics>\\n <msub>\\n <mi>O</mi>\\n <mn>2</mn>\\n </msub>\\n <annotation>$\\\\mathcal {O}_2$</annotation>\\n </semantics></math>-stable actions.</p>\",\"PeriodicalId\":55298,\"journal\":{\"name\":\"Bulletin of the London Mathematical Society\",\"volume\":\"57 2\",\"pages\":\"404-425\"},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2025-02-06\",\"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.13203\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2024/12/8 0:00:00\",\"PubModel\":\"Epub\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of the London Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1112/blms.13203","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/12/8 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Continuous actions on primitive ideal spaces lift to
C
*
$\mathrm{C}^\ast$
-actions
We prove that for any second-countable, locally compact group , any continuous -action on the primitive ideal space of a separable, nuclear -algebra such that is induced by an action on . As a direct consequence, we establish that every continuous action on the primitive ideal space of a separable, nuclear -algebra is induced by an action on a -algebra with the same primitive ideal space. Moreover, we discuss an application to the classification of equivariantly -stable actions.