{"title":"雷代方向数定理的新证明","authors":"Gábor Somlai","doi":"10.1007/s00013-024-01979-x","DOIUrl":null,"url":null,"abstract":"<div><p>Rédei and Megyesi proved that the number of directions determined by a <i>p</i>-element subset of <span>\\({\\mathbb F}_p^2\\)</span> is either 1 or at least <span>\\(\\frac{p+3}{2}\\)</span>. The same result was independently obtained by Dress, Klin, and Muzychuk. We give a new and short proof of this result using a lemma proved by Kiss and the author. The new proof relies on a result on polynomials over finite fields.</p></div>","PeriodicalId":8346,"journal":{"name":"Archiv der Mathematik","volume":"122 6","pages":""},"PeriodicalIF":0.5000,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00013-024-01979-x.pdf","citationCount":"0","resultStr":"{\"title\":\"A new proof of Rédei’s theorem on the number of directions\",\"authors\":\"Gábor Somlai\",\"doi\":\"10.1007/s00013-024-01979-x\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Rédei and Megyesi proved that the number of directions determined by a <i>p</i>-element subset of <span>\\\\({\\\\mathbb F}_p^2\\\\)</span> is either 1 or at least <span>\\\\(\\\\frac{p+3}{2}\\\\)</span>. The same result was independently obtained by Dress, Klin, and Muzychuk. We give a new and short proof of this result using a lemma proved by Kiss and the author. The new proof relies on a result on polynomials over finite fields.</p></div>\",\"PeriodicalId\":8346,\"journal\":{\"name\":\"Archiv der Mathematik\",\"volume\":\"122 6\",\"pages\":\"\"},\"PeriodicalIF\":0.5000,\"publicationDate\":\"2024-04-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://link.springer.com/content/pdf/10.1007/s00013-024-01979-x.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Archiv der Mathematik\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s00013-024-01979-x\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Archiv der Mathematik","FirstCategoryId":"100","ListUrlMain":"https://link.springer.com/article/10.1007/s00013-024-01979-x","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
A new proof of Rédei’s theorem on the number of directions
Rédei and Megyesi proved that the number of directions determined by a p-element subset of \({\mathbb F}_p^2\) is either 1 or at least \(\frac{p+3}{2}\). The same result was independently obtained by Dress, Klin, and Muzychuk. We give a new and short proof of this result using a lemma proved by Kiss and the author. The new proof relies on a result on polynomials over finite fields.
期刊介绍:
Archiv der Mathematik (AdM) publishes short high quality research papers in every area of mathematics which are not overly technical in nature and addressed to a broad readership.