{"title":"指数更大的仿射帽和射影帽","authors":"Christian Elsholtz, Gabriel F. Lipnik","doi":"10.1112/mtk.12173","DOIUrl":null,"url":null,"abstract":"<p>In spite of a recent breakthrough on upper bounds of the size of cap sets (by Croot, Lev and Pach and by Ellenberg and Gijswijt), the classical cap set constructions had not been affected. In this work, we introduce a very different method of construction for caps in all affine spaces with odd prime modulus <i>p</i>. Moreover, we show that for all primes <math>\n <semantics>\n <mrow>\n <mi>p</mi>\n <mo>≡</mo>\n <mn>5</mn>\n <mspace></mspace>\n <mi>mod</mi>\n <mspace></mspace>\n <mn>6</mn>\n </mrow>\n <annotation>$p \\equiv 5 \\bmod 6$</annotation>\n </semantics></math> with <math>\n <semantics>\n <mrow>\n <mi>p</mi>\n <mo>⩽</mo>\n <mn>41</mn>\n </mrow>\n <annotation>$p \\leqslant 41$</annotation>\n </semantics></math>, the new construction leads to an exponentially larger growth of the affine and projective caps in <math>\n <semantics>\n <mrow>\n <mi>AG</mi>\n <mo>(</mo>\n <mi>n</mi>\n <mo>,</mo>\n <mi>p</mi>\n <mo>)</mo>\n </mrow>\n <annotation>${\\rm AG}(n,p)$</annotation>\n </semantics></math> and <math>\n <semantics>\n <mrow>\n <mi>PG</mi>\n <mo>(</mo>\n <mi>n</mi>\n <mo>,</mo>\n <mi>p</mi>\n <mo>)</mo>\n </mrow>\n <annotation>${\\rm PG}(n,p)$</annotation>\n </semantics></math>. For example, when <math>\n <semantics>\n <mrow>\n <mi>p</mi>\n <mo>=</mo>\n <mn>23</mn>\n </mrow>\n <annotation>$p=23$</annotation>\n </semantics></math>, the existence of caps with growth <math>\n <semantics>\n <msup>\n <mrow>\n <mo>(</mo>\n <mn>8.0875</mn>\n <mtext>…</mtext>\n <mo>)</mo>\n </mrow>\n <mi>n</mi>\n </msup>\n <annotation>$(8.0875\\ldots )^n$</annotation>\n </semantics></math> follows from a three-dimensional example of Bose, and the only improvement had been to <math>\n <semantics>\n <msup>\n <mrow>\n <mo>(</mo>\n <mn>8.0901</mn>\n <mtext>…</mtext>\n <mo>)</mo>\n </mrow>\n <mi>n</mi>\n </msup>\n <annotation>$(8.0901\\ldots )^n$</annotation>\n </semantics></math> by Edel, based on a six-dimensional example. We improve this lower bound to <math>\n <semantics>\n <msup>\n <mrow>\n <mo>(</mo>\n <mn>9</mn>\n <mo>−</mo>\n <mi>o</mi>\n <mrow>\n <mo>(</mo>\n <mn>1</mn>\n <mo>)</mo>\n </mrow>\n <mo>)</mo>\n </mrow>\n <mi>n</mi>\n </msup>\n <annotation>$(9-o(1))^n$</annotation>\n </semantics></math>. </p>","PeriodicalId":18463,"journal":{"name":"Mathematika","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2022-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://londmathsoc.onlinelibrary.wiley.com/doi/epdf/10.1112/mtk.12173","citationCount":"2","resultStr":"{\"title\":\"Exponentially larger affine and projective caps\",\"authors\":\"Christian Elsholtz, Gabriel F. Lipnik\",\"doi\":\"10.1112/mtk.12173\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>In spite of a recent breakthrough on upper bounds of the size of cap sets (by Croot, Lev and Pach and by Ellenberg and Gijswijt), the classical cap set constructions had not been affected. In this work, we introduce a very different method of construction for caps in all affine spaces with odd prime modulus <i>p</i>. Moreover, we show that for all primes <math>\\n <semantics>\\n <mrow>\\n <mi>p</mi>\\n <mo>≡</mo>\\n <mn>5</mn>\\n <mspace></mspace>\\n <mi>mod</mi>\\n <mspace></mspace>\\n <mn>6</mn>\\n </mrow>\\n <annotation>$p \\\\equiv 5 \\\\bmod 6$</annotation>\\n </semantics></math> with <math>\\n <semantics>\\n <mrow>\\n <mi>p</mi>\\n <mo>⩽</mo>\\n <mn>41</mn>\\n </mrow>\\n <annotation>$p \\\\leqslant 41$</annotation>\\n </semantics></math>, the new construction leads to an exponentially larger growth of the affine and projective caps in <math>\\n <semantics>\\n <mrow>\\n <mi>AG</mi>\\n <mo>(</mo>\\n <mi>n</mi>\\n <mo>,</mo>\\n <mi>p</mi>\\n <mo>)</mo>\\n </mrow>\\n <annotation>${\\\\rm AG}(n,p)$</annotation>\\n </semantics></math> and <math>\\n <semantics>\\n <mrow>\\n <mi>PG</mi>\\n <mo>(</mo>\\n <mi>n</mi>\\n <mo>,</mo>\\n <mi>p</mi>\\n <mo>)</mo>\\n </mrow>\\n <annotation>${\\\\rm PG}(n,p)$</annotation>\\n </semantics></math>. For example, when <math>\\n <semantics>\\n <mrow>\\n <mi>p</mi>\\n <mo>=</mo>\\n <mn>23</mn>\\n </mrow>\\n <annotation>$p=23$</annotation>\\n </semantics></math>, the existence of caps with growth <math>\\n <semantics>\\n <msup>\\n <mrow>\\n <mo>(</mo>\\n <mn>8.0875</mn>\\n <mtext>…</mtext>\\n <mo>)</mo>\\n </mrow>\\n <mi>n</mi>\\n </msup>\\n <annotation>$(8.0875\\\\ldots )^n$</annotation>\\n </semantics></math> follows from a three-dimensional example of Bose, and the only improvement had been to <math>\\n <semantics>\\n <msup>\\n <mrow>\\n <mo>(</mo>\\n <mn>8.0901</mn>\\n <mtext>…</mtext>\\n <mo>)</mo>\\n </mrow>\\n <mi>n</mi>\\n </msup>\\n <annotation>$(8.0901\\\\ldots )^n$</annotation>\\n </semantics></math> by Edel, based on a six-dimensional example. We improve this lower bound to <math>\\n <semantics>\\n <msup>\\n <mrow>\\n <mo>(</mo>\\n <mn>9</mn>\\n <mo>−</mo>\\n <mi>o</mi>\\n <mrow>\\n <mo>(</mo>\\n <mn>1</mn>\\n <mo>)</mo>\\n </mrow>\\n <mo>)</mo>\\n </mrow>\\n <mi>n</mi>\\n </msup>\\n <annotation>$(9-o(1))^n$</annotation>\\n </semantics></math>. </p>\",\"PeriodicalId\":18463,\"journal\":{\"name\":\"Mathematika\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2022-12-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://londmathsoc.onlinelibrary.wiley.com/doi/epdf/10.1112/mtk.12173\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Mathematika\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1112/mtk.12173\",\"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":"Mathematika","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1112/mtk.12173","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
In spite of a recent breakthrough on upper bounds of the size of cap sets (by Croot, Lev and Pach and by Ellenberg and Gijswijt), the classical cap set constructions had not been affected. In this work, we introduce a very different method of construction for caps in all affine spaces with odd prime modulus p. Moreover, we show that for all primes with , the new construction leads to an exponentially larger growth of the affine and projective caps in and . For example, when , the existence of caps with growth follows from a three-dimensional example of Bose, and the only improvement had been to by Edel, based on a six-dimensional example. We improve this lower bound to .
期刊介绍:
Mathematika publishes both pure and applied mathematical articles and has done so continuously since its founding by Harold Davenport in the 1950s. The traditional emphasis has been towards the purer side of mathematics but applied mathematics and articles addressing both aspects are equally welcome. The journal is published by the London Mathematical Society, on behalf of its owner University College London, and will continue to publish research papers of the highest mathematical quality.