{"title":"作为周期类乘积的交替群 - II","authors":"Harish Kishnani, Rijubrata Kundu, Sumit Chandra Mishra","doi":"10.1007/s10801-024-01305-2","DOIUrl":null,"url":null,"abstract":"<p>Given integers <span>\\(k,l\\ge 2\\)</span>, where either <i>l</i> is odd or <i>k</i> is even, let <i>n</i>(<i>k</i>, <i>l</i>) denote the largest integer <i>n</i> such that each element of <span>\\(A_n\\)</span> is a product of <i>k</i> many <i>l</i>-cycles. M. Herzog, G. Kaplan and A. Lev conjectured that <span>\\(\\lfloor \\frac{2kl}{3} \\rfloor \\le n(k,l)\\le \\lfloor \\frac{2kl}{3}\\rfloor +1\\)</span> [Herzog et al. in J Combin Theory Ser A, 115:1235-1245 2008]. It is known that the conjecture holds when <span>\\(k=2,3,4\\)</span>. Moreover, it is also true when <span>\\(3\\mid l\\)</span>. In this article, we determine the exact value of <i>n</i>(<i>k</i>, <i>l</i>) when <span>\\(3\\not \\mid l\\)</span> and <span>\\(k\\ge 5\\)</span>. As an immediate consequence, we get that <span>\\(n(k,l)<\\lfloor \\frac{2kl}{3}\\rfloor \\)</span> when <span>\\(k\\ge 5\\)</span> and <span>\\(3\\not \\mid l\\)</span>, which shows that the above conjecture is not true in general. In fact in this case, the difference between the exact value of <i>n</i>(<i>k</i>, <i>l</i>) and the conjectured value grows linearly in terms of <i>k</i>. Our results complete the determination of <i>n</i>(<i>k</i>, <i>l</i>) for all values of <i>k</i> and <i>l</i>.</p>","PeriodicalId":14926,"journal":{"name":"Journal of Algebraic Combinatorics","volume":"41 1","pages":""},"PeriodicalIF":0.6000,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Alternating groups as products of cycle classes - II\",\"authors\":\"Harish Kishnani, Rijubrata Kundu, Sumit Chandra Mishra\",\"doi\":\"10.1007/s10801-024-01305-2\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Given integers <span>\\\\(k,l\\\\ge 2\\\\)</span>, where either <i>l</i> is odd or <i>k</i> is even, let <i>n</i>(<i>k</i>, <i>l</i>) denote the largest integer <i>n</i> such that each element of <span>\\\\(A_n\\\\)</span> is a product of <i>k</i> many <i>l</i>-cycles. M. Herzog, G. Kaplan and A. Lev conjectured that <span>\\\\(\\\\lfloor \\\\frac{2kl}{3} \\\\rfloor \\\\le n(k,l)\\\\le \\\\lfloor \\\\frac{2kl}{3}\\\\rfloor +1\\\\)</span> [Herzog et al. in J Combin Theory Ser A, 115:1235-1245 2008]. It is known that the conjecture holds when <span>\\\\(k=2,3,4\\\\)</span>. Moreover, it is also true when <span>\\\\(3\\\\mid l\\\\)</span>. In this article, we determine the exact value of <i>n</i>(<i>k</i>, <i>l</i>) when <span>\\\\(3\\\\not \\\\mid l\\\\)</span> and <span>\\\\(k\\\\ge 5\\\\)</span>. As an immediate consequence, we get that <span>\\\\(n(k,l)<\\\\lfloor \\\\frac{2kl}{3}\\\\rfloor \\\\)</span> when <span>\\\\(k\\\\ge 5\\\\)</span> and <span>\\\\(3\\\\not \\\\mid l\\\\)</span>, which shows that the above conjecture is not true in general. In fact in this case, the difference between the exact value of <i>n</i>(<i>k</i>, <i>l</i>) and the conjectured value grows linearly in terms of <i>k</i>. Our results complete the determination of <i>n</i>(<i>k</i>, <i>l</i>) for all values of <i>k</i> and <i>l</i>.</p>\",\"PeriodicalId\":14926,\"journal\":{\"name\":\"Journal of Algebraic Combinatorics\",\"volume\":\"41 1\",\"pages\":\"\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-02-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Algebraic Combinatorics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1007/s10801-024-01305-2\",\"RegionNum\":3,\"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":"Journal of Algebraic Combinatorics","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s10801-024-01305-2","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
摘要
给定整数\(k,l\ge 2\), 其中l为奇数或k为偶数,让n(k, l)表示最大整数n,使得\(A_n\)的每个元素都是k多个l循环的乘积。赫佐格(M. Herzog)、卡普兰(G. Kaplan)和列夫(A. Lev)猜想 \(lfloor \frac{2kl}{3}\n(k,l)\le \lfloor \frac{2kl}{3}\rfloor +1\)[Herzog et al. in J Combin Theory Ser A, 115:1235-1245 2008].众所周知,当 \(k=2,3,4\)时,猜想成立。此外,当 \(3\mid l\) 时猜想也成立。在本文中,我们将确定当(3,3,4)和(k,5)时n(k,l)的精确值。作为一个直接的结果,我们得到了当\(k\ge 5\) 和\(3\not \mid l\) 时的\(n(k,l)<\lfloor \frac{2kl}{3}\rfloor \),这表明上述猜想在一般情况下是不正确的。事实上,在这种情况下,n(k, l)的精确值与猜想值之间的差值是以k为单位线性增长的。我们的结果完成了对所有 k 和 l 值的 n(k,l)的确定。
Alternating groups as products of cycle classes - II
Given integers \(k,l\ge 2\), where either l is odd or k is even, let n(k, l) denote the largest integer n such that each element of \(A_n\) is a product of k many l-cycles. M. Herzog, G. Kaplan and A. Lev conjectured that \(\lfloor \frac{2kl}{3} \rfloor \le n(k,l)\le \lfloor \frac{2kl}{3}\rfloor +1\) [Herzog et al. in J Combin Theory Ser A, 115:1235-1245 2008]. It is known that the conjecture holds when \(k=2,3,4\). Moreover, it is also true when \(3\mid l\). In this article, we determine the exact value of n(k, l) when \(3\not \mid l\) and \(k\ge 5\). As an immediate consequence, we get that \(n(k,l)<\lfloor \frac{2kl}{3}\rfloor \) when \(k\ge 5\) and \(3\not \mid l\), which shows that the above conjecture is not true in general. In fact in this case, the difference between the exact value of n(k, l) and the conjectured value grows linearly in terms of k. Our results complete the determination of n(k, l) for all values of k and l.
期刊介绍:
The Journal of Algebraic Combinatorics provides a single forum for papers on algebraic combinatorics which, at present, are distributed throughout a number of journals. Within the last decade or so, algebraic combinatorics has evolved into a mature, established and identifiable area of mathematics. Research contributions in the field are increasingly seen to have substantial links with other areas of mathematics.
The journal publishes papers in which combinatorics and algebra interact in a significant and interesting fashion. This interaction might occur through the study of combinatorial structures using algebraic methods, or the application of combinatorial methods to algebraic problems.