{"title":"无爪立方图的零强制数","authors":"Mengya He , Huixian Li , Ning Song , Shengjin Ji","doi":"10.1016/j.dam.2024.08.011","DOIUrl":null,"url":null,"abstract":"<div><p>Let <span><math><mi>G</mi></math></span> be a simple graph of order <span><math><mi>n</mi></math></span>. Let <span><math><mi>S</mi></math></span> be a coloring subset of <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span>. The forcing process is that a colored vertex forces the uncolored neighbor to be colored if it has exactly one uncolored neighbor. The set <span><math><mi>S</mi></math></span> is a zero forcing set if all vertices of <span><math><mi>G</mi></math></span> become colored by iteratively applying the forcing process. The minimum size of a zero forcing set in a graph <span><math><mi>G</mi></math></span> is zero forcing number, denoted by <span><math><mrow><mi>Z</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span>, which is proposed in 2008 as a natural upper bound of the maximum nullity regarding the graph <span><math><mi>G</mi></math></span>. In the paper, we bound the zero forcing number in connected claw-free cubic graphs. More exactly if <span><math><mrow><mi>G</mi><mrow><mo>(</mo><mo>≠</mo><msub><mrow><mi>K</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>)</mo></mrow></mrow></math></span> is a connected claw-free cubic graph with order <span><math><mi>n</mi></math></span>, then we prove that <span><math><mrow><mi>Z</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>≤</mo><mi>α</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> except for three graphs with small order, and then <span><math><mrow><mi>Z</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>≤</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>4</mn></mrow></mfrac><mo>+</mo><mn>1</mn></mrow></math></span> except for three classes of graphs. In fact, our results give affirmative answers for two open problems raised by Davila and Henning.</p></div>","PeriodicalId":50573,"journal":{"name":"Discrete Applied Mathematics","volume":"359 ","pages":"Pages 321-330"},"PeriodicalIF":1.0000,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The zero forcing number of claw-free cubic graphs\",\"authors\":\"Mengya He , Huixian Li , Ning Song , Shengjin Ji\",\"doi\":\"10.1016/j.dam.2024.08.011\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Let <span><math><mi>G</mi></math></span> be a simple graph of order <span><math><mi>n</mi></math></span>. Let <span><math><mi>S</mi></math></span> be a coloring subset of <span><math><mrow><mi>V</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span>. The forcing process is that a colored vertex forces the uncolored neighbor to be colored if it has exactly one uncolored neighbor. The set <span><math><mi>S</mi></math></span> is a zero forcing set if all vertices of <span><math><mi>G</mi></math></span> become colored by iteratively applying the forcing process. The minimum size of a zero forcing set in a graph <span><math><mi>G</mi></math></span> is zero forcing number, denoted by <span><math><mrow><mi>Z</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span>, which is proposed in 2008 as a natural upper bound of the maximum nullity regarding the graph <span><math><mi>G</mi></math></span>. In the paper, we bound the zero forcing number in connected claw-free cubic graphs. More exactly if <span><math><mrow><mi>G</mi><mrow><mo>(</mo><mo>≠</mo><msub><mrow><mi>K</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>)</mo></mrow></mrow></math></span> is a connected claw-free cubic graph with order <span><math><mi>n</mi></math></span>, then we prove that <span><math><mrow><mi>Z</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>≤</mo><mi>α</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> except for three graphs with small order, and then <span><math><mrow><mi>Z</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>≤</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>4</mn></mrow></mfrac><mo>+</mo><mn>1</mn></mrow></math></span> except for three classes of graphs. In fact, our results give affirmative answers for two open problems raised by Davila and Henning.</p></div>\",\"PeriodicalId\":50573,\"journal\":{\"name\":\"Discrete Applied Mathematics\",\"volume\":\"359 \",\"pages\":\"Pages 321-330\"},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2024-08-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Discrete Applied Mathematics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0166218X24003639\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS, APPLIED\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Discrete Applied Mathematics","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0166218X24003639","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS, APPLIED","Score":null,"Total":0}
引用次数: 0
摘要
设 G 是阶数为 n 的简单图,S 是 V(G) 的着色子集。着色过程是,如果一个着色顶点正好有一个未着色的邻居,则该顶点会迫使未着色的邻居着色。如果通过迭代应用强制过程,G 的所有顶点都变成了彩色,那么集合 S 就是零强制集合。图 G 中零强制集的最小大小为零强制数,用 Z(G) 表示,它是 2008 年提出的关于图 G 的最大无效性的自然上限。更确切地说,如果 G(≠K4) 是阶数为 n 的连通无爪立方图,那么我们证明 Z(G)≤α(G) 除了三个阶数较小的图,然后 Z(G)≤n4+1 除了三类图。事实上,我们的结果给出了达维拉和亨宁提出的两个未决问题的肯定答案。
Let be a simple graph of order . Let be a coloring subset of . The forcing process is that a colored vertex forces the uncolored neighbor to be colored if it has exactly one uncolored neighbor. The set is a zero forcing set if all vertices of become colored by iteratively applying the forcing process. The minimum size of a zero forcing set in a graph is zero forcing number, denoted by , which is proposed in 2008 as a natural upper bound of the maximum nullity regarding the graph . In the paper, we bound the zero forcing number in connected claw-free cubic graphs. More exactly if is a connected claw-free cubic graph with order , then we prove that except for three graphs with small order, and then except for three classes of graphs. In fact, our results give affirmative answers for two open problems raised by Davila and Henning.
期刊介绍:
The aim of Discrete Applied Mathematics is to bring together research papers in different areas of algorithmic and applicable discrete mathematics as well as applications of combinatorial mathematics to informatics and various areas of science and technology. Contributions presented to the journal can be research papers, short notes, surveys, and possibly research problems. The "Communications" section will be devoted to the fastest possible publication of recent research results that are checked and recommended for publication by a member of the Editorial Board. The journal will also publish a limited number of book announcements as well as proceedings of conferences. These proceedings will be fully refereed and adhere to the normal standards of the journal.
Potential authors are advised to view the journal and the open calls-for-papers of special issues before submitting their manuscripts. Only high-quality, original work that is within the scope of the journal or the targeted special issue will be considered.