{"title":"有限简单群中子集积的增长","authors":"Daniele Dona, Attila Maróti, László Pyber","doi":"10.1112/blms.13093","DOIUrl":null,"url":null,"abstract":"<p>We prove that the product of a subset and a normal subset inside any finite simple non-abelian group <span></span><math>\n <semantics>\n <mi>G</mi>\n <annotation>$G$</annotation>\n </semantics></math> grows rapidly. More precisely, if <span></span><math>\n <semantics>\n <mi>A</mi>\n <annotation>$A$</annotation>\n </semantics></math> and <span></span><math>\n <semantics>\n <mi>B</mi>\n <annotation>$B$</annotation>\n </semantics></math> are two subsets with <span></span><math>\n <semantics>\n <mi>B</mi>\n <annotation>$B$</annotation>\n </semantics></math> normal and neither of them is too large inside <span></span><math>\n <semantics>\n <mi>G</mi>\n <annotation>$G$</annotation>\n </semantics></math>, then <span></span><math>\n <semantics>\n <mrow>\n <mrow>\n <mo>|</mo>\n <mi>A</mi>\n <mi>B</mi>\n <mo>|</mo>\n </mrow>\n <mo>⩾</mo>\n <msup>\n <mrow>\n <mo>|</mo>\n <mi>A</mi>\n <mo>|</mo>\n <mo>|</mo>\n <mi>B</mi>\n <mo>|</mo>\n </mrow>\n <mrow>\n <mn>1</mn>\n <mo>−</mo>\n <mi>ε</mi>\n </mrow>\n </msup>\n </mrow>\n <annotation>$|AB| \\geqslant |A||B|^{1-\\epsilon }$</annotation>\n </semantics></math> where <span></span><math>\n <semantics>\n <mrow>\n <mi>ε</mi>\n <mo>></mo>\n <mn>0</mn>\n </mrow>\n <annotation>$\\epsilon &gt;0$</annotation>\n </semantics></math> can be taken arbitrarily small. This is a somewhat surprising strengthening of a theorem of Liebeck, Schul, and Shalev.</p>","PeriodicalId":55298,"journal":{"name":"Bulletin of the London Mathematical Society","volume":"56 8","pages":"2704-2710"},"PeriodicalIF":0.8000,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Growth of products of subsets in finite simple groups\",\"authors\":\"Daniele Dona, Attila Maróti, László Pyber\",\"doi\":\"10.1112/blms.13093\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>We prove that the product of a subset and a normal subset inside any finite simple non-abelian group <span></span><math>\\n <semantics>\\n <mi>G</mi>\\n <annotation>$G$</annotation>\\n </semantics></math> grows rapidly. More precisely, if <span></span><math>\\n <semantics>\\n <mi>A</mi>\\n <annotation>$A$</annotation>\\n </semantics></math> and <span></span><math>\\n <semantics>\\n <mi>B</mi>\\n <annotation>$B$</annotation>\\n </semantics></math> are two subsets with <span></span><math>\\n <semantics>\\n <mi>B</mi>\\n <annotation>$B$</annotation>\\n </semantics></math> normal and neither of them is too large inside <span></span><math>\\n <semantics>\\n <mi>G</mi>\\n <annotation>$G$</annotation>\\n </semantics></math>, then <span></span><math>\\n <semantics>\\n <mrow>\\n <mrow>\\n <mo>|</mo>\\n <mi>A</mi>\\n <mi>B</mi>\\n <mo>|</mo>\\n </mrow>\\n <mo>⩾</mo>\\n <msup>\\n <mrow>\\n <mo>|</mo>\\n <mi>A</mi>\\n <mo>|</mo>\\n <mo>|</mo>\\n <mi>B</mi>\\n <mo>|</mo>\\n </mrow>\\n <mrow>\\n <mn>1</mn>\\n <mo>−</mo>\\n <mi>ε</mi>\\n </mrow>\\n </msup>\\n </mrow>\\n <annotation>$|AB| \\\\geqslant |A||B|^{1-\\\\epsilon }$</annotation>\\n </semantics></math> where <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>ε</mi>\\n <mo>></mo>\\n <mn>0</mn>\\n </mrow>\\n <annotation>$\\\\epsilon &gt;0$</annotation>\\n </semantics></math> can be taken arbitrarily small. This is a somewhat surprising strengthening of a theorem of Liebeck, Schul, and Shalev.</p>\",\"PeriodicalId\":55298,\"journal\":{\"name\":\"Bulletin of the London Mathematical Society\",\"volume\":\"56 8\",\"pages\":\"2704-2710\"},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2024-05-23\",\"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.13093\",\"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.13093","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
我们证明,在任何有限简单非阿贝尔群 G $G$ 内,子集与正常子集的乘积都会快速增长。更确切地说,如果 A $A$ 和 B $B$ 是两个子集,B $B$ 是正常子集,并且它们在 G $G$ 内都不是太大,那么 | A B | | | A | | B | 1 - ε $|AB| \geqslant |A||B|^{1-\epsilon }$ 其中 ε > 0 $\epsilon >0$ 可以任意取小。这是对 Liebeck、Schul 和 Shalev 的一个定理的加强,有点出人意料。
Growth of products of subsets in finite simple groups
We prove that the product of a subset and a normal subset inside any finite simple non-abelian group grows rapidly. More precisely, if and are two subsets with normal and neither of them is too large inside , then where can be taken arbitrarily small. This is a somewhat surprising strengthening of a theorem of Liebeck, Schul, and Shalev.