{"title":"Counting Parabolic Principal G-Bundles with Nilpotent Sections Over $$\\mathbb {P}^{1}$$","authors":"Rahul Singh","doi":"10.1007/s00031-024-09877-w","DOIUrl":null,"url":null,"abstract":"<p>Let <i>G</i> be a split connected reductive group over <span>\\(\\mathbb {F}_q\\)</span> and let <span>\\(\\mathbb {P}^1\\)</span> be the projective line over <span>\\(\\mathbb {F}_q\\)</span>. Firstly, we give an explicit formula for the number of <span>\\(\\mathbb {F}_{q}\\)</span>-rational points of generalized Steinberg varieties of <i>G</i>. Secondly, for each principal <i>G</i>-bundle over <span>\\(\\mathbb {P}^1\\)</span>, we give an explicit formula counting the number of triples consisting of parabolic structures at 0 and <span>\\(\\infty \\)</span> and a compatible nilpotent section of the associated adjoint bundle. In the case of <span>\\(GL_{n}\\)</span> we calculate a generating function of such volumes re-deriving a result of Mellit.</p>","PeriodicalId":49423,"journal":{"name":"Transformation Groups","volume":"71 1","pages":""},"PeriodicalIF":0.4000,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Transformation Groups","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s00031-024-09877-w","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
Let G be a split connected reductive group over \(\mathbb {F}_q\) and let \(\mathbb {P}^1\) be the projective line over \(\mathbb {F}_q\). Firstly, we give an explicit formula for the number of \(\mathbb {F}_{q}\)-rational points of generalized Steinberg varieties of G. Secondly, for each principal G-bundle over \(\mathbb {P}^1\), we give an explicit formula counting the number of triples consisting of parabolic structures at 0 and \(\infty \) and a compatible nilpotent section of the associated adjoint bundle. In the case of \(GL_{n}\) we calculate a generating function of such volumes re-deriving a result of Mellit.
期刊介绍:
Transformation Groups will only accept research articles containing new results, complete Proofs, and an abstract. Topics include: Lie groups and Lie algebras; Lie transformation groups and holomorphic transformation groups; Algebraic groups; Invariant theory; Geometry and topology of homogeneous spaces; Discrete subgroups of Lie groups; Quantum groups and enveloping algebras; Group aspects of conformal field theory; Kac-Moody groups and algebras; Lie supergroups and superalgebras.