{"title":"论哈林图的包含色度指数","authors":"Ningge Huang, Yi Tan, Lily Chen","doi":"10.1016/j.disc.2024.114266","DOIUrl":null,"url":null,"abstract":"<div><div>An inclusion-free edge-coloring of a graph <em>G</em> with <span><math><mi>δ</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>≥</mo><mn>2</mn></math></span> is a proper edge-coloring such that the set of colors incident with any vertex is not contained in the set of colors incident to any of its neighbors. The minimum number of colors needed in an inclusion-free edge-coloring of <em>G</em> is called the <span><math><mi>i</mi><mi>n</mi><mi>c</mi><mi>l</mi><mi>u</mi><mi>s</mi><mi>i</mi><mi>o</mi><mi>n</mi></math></span>-<span><math><mi>f</mi><mi>r</mi><mi>e</mi><mi>e</mi></math></span> <span><math><mi>c</mi><mi>h</mi><mi>r</mi><mi>o</mi><mi>m</mi><mi>a</mi><mi>t</mi><mi>i</mi><mi>c</mi><mspace></mspace><mi>i</mi><mi>n</mi><mi>d</mi><mi>e</mi><mi>x</mi></math></span>, denoted by <span><math><msubsup><mrow><mi>χ</mi></mrow><mrow><mo>⊂</mo></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo></math></span>. In this paper, we show that for a Halin graph <em>G</em> with maximum degree <span><math><mi>Δ</mi><mo>≥</mo><mn>4</mn></math></span>, if <em>G</em> is isomorphic to a wheel <span><math><msub><mrow><mi>W</mi></mrow><mrow><mi>Δ</mi><mo>+</mo><mn>1</mn></mrow></msub></math></span> where Δ is odd, then <span><math><msubsup><mrow><mi>χ</mi></mrow><mrow><mo>⊂</mo></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mi>Δ</mi><mo>+</mo><mn>2</mn></math></span>, otherwise <span><math><msubsup><mrow><mi>χ</mi></mrow><mrow><mo>⊂</mo></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mi>Δ</mi><mo>+</mo><mn>1</mn></math></span>. We also show a special cubic Halin graph with <span><math><msubsup><mrow><mi>χ</mi></mrow><mrow><mo>⊂</mo></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mn>5</mn></math></span>.</div></div>","PeriodicalId":50572,"journal":{"name":"Discrete Mathematics","volume":"348 2","pages":"Article 114266"},"PeriodicalIF":0.7000,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On the inclusion chromatic index of a Halin graph\",\"authors\":\"Ningge Huang, Yi Tan, Lily Chen\",\"doi\":\"10.1016/j.disc.2024.114266\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>An inclusion-free edge-coloring of a graph <em>G</em> with <span><math><mi>δ</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>≥</mo><mn>2</mn></math></span> is a proper edge-coloring such that the set of colors incident with any vertex is not contained in the set of colors incident to any of its neighbors. The minimum number of colors needed in an inclusion-free edge-coloring of <em>G</em> is called the <span><math><mi>i</mi><mi>n</mi><mi>c</mi><mi>l</mi><mi>u</mi><mi>s</mi><mi>i</mi><mi>o</mi><mi>n</mi></math></span>-<span><math><mi>f</mi><mi>r</mi><mi>e</mi><mi>e</mi></math></span> <span><math><mi>c</mi><mi>h</mi><mi>r</mi><mi>o</mi><mi>m</mi><mi>a</mi><mi>t</mi><mi>i</mi><mi>c</mi><mspace></mspace><mi>i</mi><mi>n</mi><mi>d</mi><mi>e</mi><mi>x</mi></math></span>, denoted by <span><math><msubsup><mrow><mi>χ</mi></mrow><mrow><mo>⊂</mo></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo></math></span>. In this paper, we show that for a Halin graph <em>G</em> with maximum degree <span><math><mi>Δ</mi><mo>≥</mo><mn>4</mn></math></span>, if <em>G</em> is isomorphic to a wheel <span><math><msub><mrow><mi>W</mi></mrow><mrow><mi>Δ</mi><mo>+</mo><mn>1</mn></mrow></msub></math></span> where Δ is odd, then <span><math><msubsup><mrow><mi>χ</mi></mrow><mrow><mo>⊂</mo></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mi>Δ</mi><mo>+</mo><mn>2</mn></math></span>, otherwise <span><math><msubsup><mrow><mi>χ</mi></mrow><mrow><mo>⊂</mo></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mi>Δ</mi><mo>+</mo><mn>1</mn></math></span>. We also show a special cubic Halin graph with <span><math><msubsup><mrow><mi>χ</mi></mrow><mrow><mo>⊂</mo></mrow><mrow><mo>′</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mn>5</mn></math></span>.</div></div>\",\"PeriodicalId\":50572,\"journal\":{\"name\":\"Discrete Mathematics\",\"volume\":\"348 2\",\"pages\":\"Article 114266\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2024-09-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Discrete Mathematics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0012365X24003972\",\"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":"Discrete Mathematics","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0012365X24003972","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
摘要
δ(G)≥2的图 G 的无包含边着色是一种适当的边着色,使得任何顶点的颜色集合都不包含在其任何相邻顶点的颜色集合中。G 的无包含边染色所需的最少颜色数称为无包含色度指数,用 χ⊂′(G)表示。在本文中,我们证明了对于最大度数为 Δ≥4 的 Halin 图 G,如果 G 与 Δ 为奇数的轮 WΔ+1 同构,则 χ⊂′(G)=Δ+2 ,否则 χ⊂′(G)=Δ+1。我们还展示了一个特殊的立方哈林图,其χ⊂′(G)=5。
An inclusion-free edge-coloring of a graph G with is a proper edge-coloring such that the set of colors incident with any vertex is not contained in the set of colors incident to any of its neighbors. The minimum number of colors needed in an inclusion-free edge-coloring of G is called the - , denoted by . In this paper, we show that for a Halin graph G with maximum degree , if G is isomorphic to a wheel where Δ is odd, then , otherwise . We also show a special cubic Halin graph with .
期刊介绍:
Discrete Mathematics provides a common forum for significant research in many areas of discrete mathematics and combinatorics. Among the fields covered by Discrete Mathematics are graph and hypergraph theory, enumeration, coding theory, block designs, the combinatorics of partially ordered sets, extremal set theory, matroid theory, algebraic combinatorics, discrete geometry, matrices, and discrete probability theory.
Items in the journal include research articles (Contributions or Notes, depending on length) and survey/expository articles (Perspectives). Efforts are made to process the submission of Notes (short articles) quickly. The Perspectives section features expository articles accessible to a broad audience that cast new light or present unifying points of view on well-known or insufficiently-known topics.