{"title":"论凯勒微分卷的无扭性","authors":"Nilkantha Das, Sumit Roy","doi":"10.1112/blms.13114","DOIUrl":null,"url":null,"abstract":"<p>Let <span></span><math>\n <semantics>\n <mi>X</mi>\n <annotation>$X$</annotation>\n </semantics></math> be a normal algebraic variety over an algebraically closed field <span></span><math>\n <semantics>\n <mi>k</mi>\n <annotation>$k$</annotation>\n </semantics></math>. We prove that the Kähler differential sheaf of <span></span><math>\n <semantics>\n <mi>X</mi>\n <annotation>$X$</annotation>\n </semantics></math> is torsion-free if and only if any regular section of the ideal sheaf of the first order deformation of <span></span><math>\n <semantics>\n <mi>X</mi>\n <annotation>$X$</annotation>\n </semantics></math> inside <span></span><math>\n <semantics>\n <mrow>\n <mi>X</mi>\n <msub>\n <mo>×</mo>\n <mi>k</mi>\n </msub>\n <mi>X</mi>\n </mrow>\n <annotation>$X\\times _k X$</annotation>\n </semantics></math>, defined outside the singular locus of <span></span><math>\n <semantics>\n <mrow>\n <mi>X</mi>\n <msub>\n <mo>×</mo>\n <mi>k</mi>\n </msub>\n <mi>X</mi>\n </mrow>\n <annotation>$X \\times _k X$</annotation>\n </semantics></math>, extends regularly to the singular locus.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"56 9","pages":"2982-2990"},"PeriodicalIF":0.8000,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On torsion-freeness of Kähler differential sheaves\",\"authors\":\"Nilkantha Das, Sumit Roy\",\"doi\":\"10.1112/blms.13114\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Let <span></span><math>\\n <semantics>\\n <mi>X</mi>\\n <annotation>$X$</annotation>\\n </semantics></math> be a normal algebraic variety over an algebraically closed field <span></span><math>\\n <semantics>\\n <mi>k</mi>\\n <annotation>$k$</annotation>\\n </semantics></math>. We prove that the Kähler differential sheaf of <span></span><math>\\n <semantics>\\n <mi>X</mi>\\n <annotation>$X$</annotation>\\n </semantics></math> is torsion-free if and only if any regular section of the ideal sheaf of the first order deformation of <span></span><math>\\n <semantics>\\n <mi>X</mi>\\n <annotation>$X$</annotation>\\n </semantics></math> inside <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>X</mi>\\n <msub>\\n <mo>×</mo>\\n <mi>k</mi>\\n </msub>\\n <mi>X</mi>\\n </mrow>\\n <annotation>$X\\\\times _k X$</annotation>\\n </semantics></math>, defined outside the singular locus of <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>X</mi>\\n <msub>\\n <mo>×</mo>\\n <mi>k</mi>\\n </msub>\\n <mi>X</mi>\\n </mrow>\\n <annotation>$X \\\\times _k X$</annotation>\\n </semantics></math>, extends regularly to the singular locus.</p>\",\"PeriodicalId\":55298,\"journal\":{\"name\":\"Bulletin of the London Mathematical Society\",\"volume\":\"56 9\",\"pages\":\"2982-2990\"},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2024-07-02\",\"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.13114\",\"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://onlinelibrary.wiley.com/doi/10.1112/blms.13114","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
摘要
设 X $X$ 是代数闭域 k $k$ 上的正态代数簇。我们证明,当且仅当在 X × k X $X \times _k X$ 的奇异点外定义的 X × k X $X \times _k X$ 内 X $X$ 一阶变形的理想舍夫的任何正则截面正则地延伸到奇异点时,X $X$ 的凯勒微分舍夫是无扭转的。
On torsion-freeness of Kähler differential sheaves
Let be a normal algebraic variety over an algebraically closed field . We prove that the Kähler differential sheaf of is torsion-free if and only if any regular section of the ideal sheaf of the first order deformation of inside , defined outside the singular locus of , extends regularly to the singular locus.