{"title":"G - a - G - m$ \\mathbb {G}_a\\r乘以\\mathbb {G}_m$的几何不变量理论","authors":"Yikun Qiao","doi":"10.1112/blms.70065","DOIUrl":null,"url":null,"abstract":"<p>We study geometric invariant theory for <span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>G</mi>\n <mi>a</mi>\n </msub>\n <msub>\n <mo>⋊</mo>\n <mi>d</mi>\n </msub>\n <msub>\n <mi>G</mi>\n <mi>m</mi>\n </msub>\n </mrow>\n <annotation>$\\mathbb {G}_a\\rtimes _d\\mathbb {G}_m$</annotation>\n </semantics></math> over characteristic zero. For a <span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>G</mi>\n <mi>a</mi>\n </msub>\n <msub>\n <mo>⋊</mo>\n <mi>d</mi>\n </msub>\n <msub>\n <mi>G</mi>\n <mi>m</mi>\n </msub>\n </mrow>\n <annotation>$\\mathbb {G}_a\\rtimes _d\\mathbb {G}_m$</annotation>\n </semantics></math>-action on a variety <span></span><math>\n <semantics>\n <mi>C</mi>\n <annotation>$C$</annotation>\n </semantics></math> in suitable case, we provide an equivariant birational modification <span></span><math>\n <semantics>\n <mrow>\n <mi>p</mi>\n <mo>:</mo>\n <msup>\n <mi>C</mi>\n <mo>′</mo>\n </msup>\n <mo>→</mo>\n <mi>C</mi>\n </mrow>\n <annotation>$p:C^{\\prime }\\rightarrow C$</annotation>\n </semantics></math> such that <span></span><math>\n <semantics>\n <mrow>\n <msup>\n <mi>C</mi>\n <mo>′</mo>\n </msup>\n <mo>→</mo>\n <msup>\n <mi>C</mi>\n <mo>′</mo>\n </msup>\n <mo>/</mo>\n <msub>\n <mi>G</mi>\n <mi>a</mi>\n </msub>\n </mrow>\n <annotation>$C^{\\prime }\\rightarrow C^{\\prime }/\\mathbb {G}_a$</annotation>\n </semantics></math> is a principal bundle. The situation covers quotients of unstable strata of any linear <span></span><math>\n <semantics>\n <msub>\n <mi>SL</mi>\n <mn>2</mn>\n </msub>\n <annotation>$\\mathrm{SL}_2$</annotation>\n </semantics></math>-action.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"57 6","pages":"1856-1884"},"PeriodicalIF":0.9000,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Geometric invariant theory for \\n \\n \\n \\n G\\n a\\n \\n ⋊\\n \\n G\\n m\\n \\n \\n $\\\\mathbb {G}_a\\\\rtimes \\\\mathbb {G}_m$\",\"authors\":\"Yikun Qiao\",\"doi\":\"10.1112/blms.70065\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We study geometric invariant theory for <span></span><math>\\n <semantics>\\n <mrow>\\n <msub>\\n <mi>G</mi>\\n <mi>a</mi>\\n </msub>\\n <msub>\\n <mo>⋊</mo>\\n <mi>d</mi>\\n </msub>\\n <msub>\\n <mi>G</mi>\\n <mi>m</mi>\\n </msub>\\n </mrow>\\n <annotation>$\\\\mathbb {G}_a\\\\rtimes _d\\\\mathbb {G}_m$</annotation>\\n </semantics></math> over characteristic zero. For a <span></span><math>\\n <semantics>\\n <mrow>\\n <msub>\\n <mi>G</mi>\\n <mi>a</mi>\\n </msub>\\n <msub>\\n <mo>⋊</mo>\\n <mi>d</mi>\\n </msub>\\n <msub>\\n <mi>G</mi>\\n <mi>m</mi>\\n </msub>\\n </mrow>\\n <annotation>$\\\\mathbb {G}_a\\\\rtimes _d\\\\mathbb {G}_m$</annotation>\\n </semantics></math>-action on a variety <span></span><math>\\n <semantics>\\n <mi>C</mi>\\n <annotation>$C$</annotation>\\n </semantics></math> in suitable case, we provide an equivariant birational modification <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>p</mi>\\n <mo>:</mo>\\n <msup>\\n <mi>C</mi>\\n <mo>′</mo>\\n </msup>\\n <mo>→</mo>\\n <mi>C</mi>\\n </mrow>\\n <annotation>$p:C^{\\\\prime }\\\\rightarrow C$</annotation>\\n </semantics></math> such that <span></span><math>\\n <semantics>\\n <mrow>\\n <msup>\\n <mi>C</mi>\\n <mo>′</mo>\\n </msup>\\n <mo>→</mo>\\n <msup>\\n <mi>C</mi>\\n <mo>′</mo>\\n </msup>\\n <mo>/</mo>\\n <msub>\\n <mi>G</mi>\\n <mi>a</mi>\\n </msub>\\n </mrow>\\n <annotation>$C^{\\\\prime }\\\\rightarrow C^{\\\\prime }/\\\\mathbb {G}_a$</annotation>\\n </semantics></math> is a principal bundle. The situation covers quotients of unstable strata of any linear <span></span><math>\\n <semantics>\\n <msub>\\n <mi>SL</mi>\\n <mn>2</mn>\\n </msub>\\n <annotation>$\\\\mathrm{SL}_2$</annotation>\\n </semantics></math>-action.</p>\",\"PeriodicalId\":55298,\"journal\":{\"name\":\"Bulletin of the London Mathematical Society\",\"volume\":\"57 6\",\"pages\":\"1856-1884\"},\"PeriodicalIF\":0.9000,\"publicationDate\":\"2025-04-08\",\"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://londmathsoc.onlinelibrary.wiley.com/doi/10.1112/blms.70065\",\"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.70065","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
我们研究了G a d G m$ \mathbb {G}_a\r乘以d\mathbb {G}_m$在特征零上的几何不变理论。在合适的情况下,对于G a d G m \mathbb {G}_a\ rx乘以d\mathbb {G}_m$ -作用于C$ C$,我们提供了一个等变双元修正p:C ‘→C$ p:C^{\ ’}\右C$使得C ‘→C ’ / G a$C^{\prime}\右row C^{\prime}/\mathbb {G}_a$是一个主束。这种情况涵盖了任意线性SL 2$ \ mathm {SL}_2$ -作用的不稳定层商。
Geometric invariant theory for
G
a
⋊
G
m
$\mathbb {G}_a\rtimes \mathbb {G}_m$
We study geometric invariant theory for over characteristic zero. For a -action on a variety in suitable case, we provide an equivariant birational modification such that is a principal bundle. The situation covers quotients of unstable strata of any linear -action.