{"title":"融合系统特征类产生的上同调子谱","authors":"Ian J. Leary, Jason Semeraro","doi":"10.1112/blms.70074","DOIUrl":null,"url":null,"abstract":"<p>If <span></span><math>\n <semantics>\n <mi>F</mi>\n <annotation>$\\mathcal {F}$</annotation>\n </semantics></math> is a saturated fusion system on a finite <span></span><math>\n <semantics>\n <mi>p</mi>\n <annotation>$p$</annotation>\n </semantics></math>-group <span></span><math>\n <semantics>\n <mi>S</mi>\n <annotation>$S$</annotation>\n </semantics></math>, we define the Chern subring <span></span><math>\n <semantics>\n <mrow>\n <mo>Ch</mo>\n <mo>(</mo>\n <mi>F</mi>\n <mo>)</mo>\n </mrow>\n <annotation>${\\operatorname{Ch}}(\\mathcal {F})$</annotation>\n </semantics></math> of <span></span><math>\n <semantics>\n <mi>F</mi>\n <annotation>$\\mathcal {F}$</annotation>\n </semantics></math> to be the subring of <span></span><math>\n <semantics>\n <mrow>\n <msup>\n <mi>H</mi>\n <mo>∗</mo>\n </msup>\n <mrow>\n <mo>(</mo>\n <mi>S</mi>\n <mo>;</mo>\n <msub>\n <mi>F</mi>\n <mi>p</mi>\n </msub>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation>$H^*(S;{\\mathbb {F}}_p)$</annotation>\n </semantics></math> generated by Chern classes of <span></span><math>\n <semantics>\n <mi>F</mi>\n <annotation>$\\mathcal {F}$</annotation>\n </semantics></math>-stable representations of <span></span><math>\n <semantics>\n <mi>S</mi>\n <annotation>$S$</annotation>\n </semantics></math>. We show that <span></span><math>\n <semantics>\n <mrow>\n <mo>Ch</mo>\n <mo>(</mo>\n <mi>F</mi>\n <mo>)</mo>\n </mrow>\n <annotation>${\\operatorname{Ch}}(\\mathcal {F})$</annotation>\n </semantics></math> is contained in <span></span><math>\n <semantics>\n <mrow>\n <msup>\n <mi>H</mi>\n <mo>∗</mo>\n </msup>\n <mrow>\n <mo>(</mo>\n <mi>F</mi>\n <mo>;</mo>\n <msub>\n <mi>F</mi>\n <mi>p</mi>\n </msub>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation>$H^*(\\mathcal {F};{\\mathbb {F}}_p)$</annotation>\n </semantics></math> and apply a result of Green and the first author to describe its maximal ideal spectrum in terms of a certain category of elementary abelian subgroups. We obtain similar results for various related subrings, including those generated by characteristic classes of <span></span><math>\n <semantics>\n <mi>F</mi>\n <annotation>$\\mathcal {F}$</annotation>\n </semantics></math>-stable <span></span><math>\n <semantics>\n <mi>S</mi>\n <annotation>$S$</annotation>\n </semantics></math>-sets.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 7","pages":"1990-2005"},"PeriodicalIF":0.9000,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.70074","citationCount":"0","resultStr":"{\"title\":\"Spectra of subrings of cohomology generated by characteristic classes for fusion systems\",\"authors\":\"Ian J. Leary, Jason Semeraro\",\"doi\":\"10.1112/blms.70074\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>If <span></span><math>\\n <semantics>\\n <mi>F</mi>\\n <annotation>$\\\\mathcal {F}$</annotation>\\n </semantics></math> is a saturated fusion system on a finite <span></span><math>\\n <semantics>\\n <mi>p</mi>\\n <annotation>$p$</annotation>\\n </semantics></math>-group <span></span><math>\\n <semantics>\\n <mi>S</mi>\\n <annotation>$S$</annotation>\\n </semantics></math>, we define the Chern subring <span></span><math>\\n <semantics>\\n <mrow>\\n <mo>Ch</mo>\\n <mo>(</mo>\\n <mi>F</mi>\\n <mo>)</mo>\\n </mrow>\\n <annotation>${\\\\operatorname{Ch}}(\\\\mathcal {F})$</annotation>\\n </semantics></math> of <span></span><math>\\n <semantics>\\n <mi>F</mi>\\n <annotation>$\\\\mathcal {F}$</annotation>\\n </semantics></math> to be the subring of <span></span><math>\\n <semantics>\\n <mrow>\\n <msup>\\n <mi>H</mi>\\n <mo>∗</mo>\\n </msup>\\n <mrow>\\n <mo>(</mo>\\n <mi>S</mi>\\n <mo>;</mo>\\n <msub>\\n <mi>F</mi>\\n <mi>p</mi>\\n </msub>\\n <mo>)</mo>\\n </mrow>\\n </mrow>\\n <annotation>$H^*(S;{\\\\mathbb {F}}_p)$</annotation>\\n </semantics></math> generated by Chern classes of <span></span><math>\\n <semantics>\\n <mi>F</mi>\\n <annotation>$\\\\mathcal {F}$</annotation>\\n </semantics></math>-stable representations of <span></span><math>\\n <semantics>\\n <mi>S</mi>\\n <annotation>$S$</annotation>\\n </semantics></math>. We show that <span></span><math>\\n <semantics>\\n <mrow>\\n <mo>Ch</mo>\\n <mo>(</mo>\\n <mi>F</mi>\\n <mo>)</mo>\\n </mrow>\\n <annotation>${\\\\operatorname{Ch}}(\\\\mathcal {F})$</annotation>\\n </semantics></math> is contained in <span></span><math>\\n <semantics>\\n <mrow>\\n <msup>\\n <mi>H</mi>\\n <mo>∗</mo>\\n </msup>\\n <mrow>\\n <mo>(</mo>\\n <mi>F</mi>\\n <mo>;</mo>\\n <msub>\\n <mi>F</mi>\\n <mi>p</mi>\\n </msub>\\n <mo>)</mo>\\n </mrow>\\n </mrow>\\n <annotation>$H^*(\\\\mathcal {F};{\\\\mathbb {F}}_p)$</annotation>\\n </semantics></math> and apply a result of Green and the first author to describe its maximal ideal spectrum in terms of a certain category of elementary abelian subgroups. We obtain similar results for various related subrings, including those generated by characteristic classes of <span></span><math>\\n <semantics>\\n <mi>F</mi>\\n <annotation>$\\\\mathcal {F}$</annotation>\\n </semantics></math>-stable <span></span><math>\\n <semantics>\\n <mi>S</mi>\\n <annotation>$S$</annotation>\\n </semantics></math>-sets.</p>\",\"PeriodicalId\":55298,\"journal\":{\"name\":\"Bulletin of the London Mathematical Society\",\"volume\":\"57 7\",\"pages\":\"1990-2005\"},\"PeriodicalIF\":0.9000,\"publicationDate\":\"2025-04-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://onlinelibrary.wiley.com/doi/epdf/10.1112/blms.70074\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Bulletin of the London Mathematical Society\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://londmathsoc.onlinelibrary.wiley.com/doi/10.1112/blms.70074\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of the London Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://londmathsoc.onlinelibrary.wiley.com/doi/10.1112/blms.70074","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Spectra of subrings of cohomology generated by characteristic classes for fusion systems
If is a saturated fusion system on a finite -group , we define the Chern subring of to be the subring of generated by Chern classes of -stable representations of . We show that is contained in and apply a result of Green and the first author to describe its maximal ideal spectrum in terms of a certain category of elementary abelian subgroups. We obtain similar results for various related subrings, including those generated by characteristic classes of -stable -sets.