{"title":"$$K_4$$ 小自由图的注入色度指数","authors":"Jian-Bo Lv, Jiacong Fu, Jianxi Li","doi":"10.1007/s00373-024-02807-3","DOIUrl":null,"url":null,"abstract":"<p>An edge-coloring of a graph <i>G</i> is <i>injective</i> if for any two distinct edges <span>\\(e_1\\)</span> and <span>\\(e_2\\)</span>, the colors of <span>\\(e_1\\)</span> and <span>\\(e_2\\)</span> are distinct if they are at distance 2 in <i>G</i> or in a common triangle. The injective chromatic index of <i>G</i>, <span>\\(\\chi ^\\prime _{inj}(G)\\)</span>, is the minimum number of colors needed for an injective edge-coloring of <i>G</i>. In this note, we show that every <span>\\(K_4\\)</span>-minor free graph <i>G</i> with maximum degree <span>\\(\\Delta (G)\\ge 3\\)</span> satisfies <span>\\(\\chi ^\\prime _{inj}(G)\\le 2\\Delta (G)+1\\)</span>.</p>","PeriodicalId":12811,"journal":{"name":"Graphs and Combinatorics","volume":"21 1","pages":""},"PeriodicalIF":0.6000,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Injective Chromatic Index of $$K_4$$ -Minor Free Graphs\",\"authors\":\"Jian-Bo Lv, Jiacong Fu, Jianxi Li\",\"doi\":\"10.1007/s00373-024-02807-3\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>An edge-coloring of a graph <i>G</i> is <i>injective</i> if for any two distinct edges <span>\\\\(e_1\\\\)</span> and <span>\\\\(e_2\\\\)</span>, the colors of <span>\\\\(e_1\\\\)</span> and <span>\\\\(e_2\\\\)</span> are distinct if they are at distance 2 in <i>G</i> or in a common triangle. The injective chromatic index of <i>G</i>, <span>\\\\(\\\\chi ^\\\\prime _{inj}(G)\\\\)</span>, is the minimum number of colors needed for an injective edge-coloring of <i>G</i>. In this note, we show that every <span>\\\\(K_4\\\\)</span>-minor free graph <i>G</i> with maximum degree <span>\\\\(\\\\Delta (G)\\\\ge 3\\\\)</span> satisfies <span>\\\\(\\\\chi ^\\\\prime _{inj}(G)\\\\le 2\\\\Delta (G)+1\\\\)</span>.</p>\",\"PeriodicalId\":12811,\"journal\":{\"name\":\"Graphs and Combinatorics\",\"volume\":\"21 1\",\"pages\":\"\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2024-06-04\",\"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/s00373-024-02807-3\",\"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/s00373-024-02807-3","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
如果对于任意两条不同的边\(e_1\)和\(e_2\)来说,如果它们在 G 中的距离是 2 或者在一个共同的三角形中,那么它们的颜色就是不同的,那么图 G 的边着色就是可注入的。G 的注入色度指数((\chi ^\prime _{inj}(G)\))是 G 的注入边着色所需的最少颜色数。在本说明中,我们证明了每个具有最大度的\(\Delta (G)\ge 3\) 的\(K_4\)-minor free graph G 都满足\(\chi ^\prime _{inj}(G)\le 2\Delta (G)+1\)。
Injective Chromatic Index of $$K_4$$ -Minor Free Graphs
An edge-coloring of a graph G is injective if for any two distinct edges \(e_1\) and \(e_2\), the colors of \(e_1\) and \(e_2\) are distinct if they are at distance 2 in G or in a common triangle. The injective chromatic index of G, \(\chi ^\prime _{inj}(G)\), is the minimum number of colors needed for an injective edge-coloring of G. In this note, we show that every \(K_4\)-minor free graph G with maximum degree \(\Delta (G)\ge 3\) satisfies \(\chi ^\prime _{inj}(G)\le 2\Delta (G)+1\).
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.