{"title":"LULU是同义词","authors":"E. Javier Elizondo , Paulo Lima-Filho","doi":"10.1016/j.jpaa.2025.107880","DOIUrl":null,"url":null,"abstract":"<div><div>Let <em>G</em> be a Chevalley group over a field <span><math><mi>k</mi></math></span>. Fix a maximal torus <span><math><mi>T</mi></math></span> in <em>G</em>, along with opposite Borel subgroups <em>B</em> and <span><math><msup><mrow><mi>B</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> satisfying <span><math><mi>T</mi><mo>=</mo><mi>B</mi><mo>∩</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span>, and denote by <span><math><mi>U</mi><mo>:</mo><mo>=</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>(</mo><mi>B</mi><mo>)</mo></math></span> and <span><math><mi>L</mi><mo>:</mo><mo>=</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>)</mo></math></span> their respective unipotent radicals. We prove that the multiplication map <span><math><mi>μ</mi><mo>:</mo><mi>L</mi><mo>×</mo><mi>U</mi><mo>×</mo><mi>L</mi><mo>×</mo><mi>U</mi><mo>⟶</mo><mi>G</mi></math></span> is syntomic and faithfully flat over any base field <span><math><mi>k</mi></math></span>.</div></div>","PeriodicalId":54770,"journal":{"name":"Journal of Pure and Applied Algebra","volume":"229 2","pages":"Article 107880"},"PeriodicalIF":0.7000,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"LULU is syntomic\",\"authors\":\"E. Javier Elizondo , Paulo Lima-Filho\",\"doi\":\"10.1016/j.jpaa.2025.107880\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Let <em>G</em> be a Chevalley group over a field <span><math><mi>k</mi></math></span>. Fix a maximal torus <span><math><mi>T</mi></math></span> in <em>G</em>, along with opposite Borel subgroups <em>B</em> and <span><math><msup><mrow><mi>B</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> satisfying <span><math><mi>T</mi><mo>=</mo><mi>B</mi><mo>∩</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span>, and denote by <span><math><mi>U</mi><mo>:</mo><mo>=</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>(</mo><mi>B</mi><mo>)</mo></math></span> and <span><math><mi>L</mi><mo>:</mo><mo>=</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>)</mo></math></span> their respective unipotent radicals. We prove that the multiplication map <span><math><mi>μ</mi><mo>:</mo><mi>L</mi><mo>×</mo><mi>U</mi><mo>×</mo><mi>L</mi><mo>×</mo><mi>U</mi><mo>⟶</mo><mi>G</mi></math></span> is syntomic and faithfully flat over any base field <span><math><mi>k</mi></math></span>.</div></div>\",\"PeriodicalId\":54770,\"journal\":{\"name\":\"Journal of Pure and Applied Algebra\",\"volume\":\"229 2\",\"pages\":\"Article 107880\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2025-02-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Pure and Applied Algebra\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022404925000192\",\"RegionNum\":2,\"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":"Journal of Pure and Applied Algebra","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022404925000192","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Let G be a Chevalley group over a field . Fix a maximal torus in G, along with opposite Borel subgroups B and satisfying , and denote by and their respective unipotent radicals. We prove that the multiplication map is syntomic and faithfully flat over any base field .
期刊介绍：
The Journal of Pure and Applied Algebra concentrates on that part of algebra likely to be of general mathematical interest: algebraic results with immediate applications, and the development of algebraic theories of sufficiently general relevance to allow for future applications.
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