{"title":"组件中多个图形副本的拉姆齐数","authors":"Caixia Huang, Yuejian Peng, Yiran Zhang","doi":"10.1007/s00373-024-02821-5","DOIUrl":null,"url":null,"abstract":"<p>For a graph <i>G</i>, let <span>\\(R({\\mathcal {C}}(nG))\\)</span> denote the least <i>N</i> such that every 2-colouring of the edges of <span>\\(K_N\\)</span> contains a monochromatic copy of <i>nG</i> in a monochromatic connected subgraph, where <i>nG</i> denotes <i>n</i> vertex disjoint copies of <i>G</i>. Gyárfás and Sárközy (J Graph Theory 83(2):109–119, 2016) showed that <span>\\(R({\\mathcal {C}}(nK_3))=7n-2\\)</span> for <span>\\(n \\ge 2\\)</span>. After that, Roberts (Electron J Comb 24(1):8, 2017)showed that <span>\\(R({\\mathcal {C}}(nK_r))=(r^2-r+1)n-r+1\\)</span> for <span>\\(r \\ge 4\\)</span> and <span>\\(n \\ge R(K_r)\\)</span>, where <span>\\(R(K_r)\\)</span> is the Ramsey number of <span>\\(K_r\\)</span>. In this paper, we determine <span>\\(R({\\mathcal {C}}(nG))\\)</span> for all 4-vertex graphs <i>G</i> without isolated vertices.</p>","PeriodicalId":12811,"journal":{"name":"Graphs and Combinatorics","volume":"19 1","pages":""},"PeriodicalIF":0.6000,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Ramsey Numbers of Multiple Copies of Graphs in a Component\",\"authors\":\"Caixia Huang, Yuejian Peng, Yiran Zhang\",\"doi\":\"10.1007/s00373-024-02821-5\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>For a graph <i>G</i>, let <span>\\\\(R({\\\\mathcal {C}}(nG))\\\\)</span> denote the least <i>N</i> such that every 2-colouring of the edges of <span>\\\\(K_N\\\\)</span> contains a monochromatic copy of <i>nG</i> in a monochromatic connected subgraph, where <i>nG</i> denotes <i>n</i> vertex disjoint copies of <i>G</i>. Gyárfás and Sárközy (J Graph Theory 83(2):109–119, 2016) showed that <span>\\\\(R({\\\\mathcal {C}}(nK_3))=7n-2\\\\)</span> for <span>\\\\(n \\\\ge 2\\\\)</span>. After that, Roberts (Electron J Comb 24(1):8, 2017)showed that <span>\\\\(R({\\\\mathcal {C}}(nK_r))=(r^2-r+1)n-r+1\\\\)</span> for <span>\\\\(r \\\\ge 4\\\\)</span> and <span>\\\\(n \\\\ge R(K_r)\\\\)</span>, where <span>\\\\(R(K_r)\\\\)</span> is the Ramsey number of <span>\\\\(K_r\\\\)</span>. In this paper, we determine <span>\\\\(R({\\\\mathcal {C}}(nG))\\\\)</span> for all 4-vertex graphs <i>G</i> without isolated vertices.</p>\",\"PeriodicalId\":12811,\"journal\":{\"name\":\"Graphs and Combinatorics\",\"volume\":\"19 1\",\"pages\":\"\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-08-07\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Graphs and Combinatorics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1007/s00373-024-02821-5\",\"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":"Graphs and Combinatorics","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s00373-024-02821-5","RegionNum":4,"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
对于一个图 G,让 \(R({\mathcal {C}}(nG))\ 表示这样的最小 N,即 \(K_N\) 的边的每一个 2 色包含一个单色连接子图中 nG 的单色副本,其中 nG 表示 G 的 n 个顶点不相交副本。Gyárfás 和 Sárközy (J Graph Theory 83(2):109-119, 2016) 证明了 \(R({mathcal {C}}(nK_3))=7n-2\) for \(n \ge 2\).之后,罗伯茨(Electron J Comb 24(1):8, 2017)证明了对于\(r \ge 4\) 和\(n \ge R(K_r)\),\(R({\mathcal {C}}(nK_r))=(r^2-r+1)n-r+1\) ,其中\(R(K_r)\)是\(K_r\)的拉姆齐数。在本文中,我们确定了所有没有孤立顶点的 4 顶点图 G 的 \(R({\mathcal {C}}(nG))\) 。
Ramsey Numbers of Multiple Copies of Graphs in a Component
For a graph G, let \(R({\mathcal {C}}(nG))\) denote the least N such that every 2-colouring of the edges of \(K_N\) contains a monochromatic copy of nG in a monochromatic connected subgraph, where nG denotes n vertex disjoint copies of G. Gyárfás and Sárközy (J Graph Theory 83(2):109–119, 2016) showed that \(R({\mathcal {C}}(nK_3))=7n-2\) for \(n \ge 2\). After that, Roberts (Electron J Comb 24(1):8, 2017)showed that \(R({\mathcal {C}}(nK_r))=(r^2-r+1)n-r+1\) for \(r \ge 4\) and \(n \ge R(K_r)\), where \(R(K_r)\) is the Ramsey number of \(K_r\). In this paper, we determine \(R({\mathcal {C}}(nG))\) for all 4-vertex graphs G without isolated vertices.
期刊介绍:
Graphs and Combinatorics is an international journal devoted to research concerning all aspects of combinatorial mathematics. In addition to original research papers, the journal also features survey articles from authors invited by the editorial board.