{"title":"关于图中 {K2,C2i+1:i≥1} 因子的一些结果","authors":"Xiaoyun Lv , Jianxi Li , Shou-Jun Xu","doi":"10.1016/j.dam.2024.08.021","DOIUrl":null,"url":null,"abstract":"<div><p>An <span><math><mrow><mo>{</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>,</mo><mo>…</mo><mo>}</mo></mrow></math></span>-factor of a graph <span><math><mi>G</mi></math></span> is defined to be a spanning subgraph of <span><math><mi>G</mi></math></span> such that each component of which is isomorphic to one of <span><math><mrow><mo>{</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>,</mo><mo>…</mo><mo>}</mo></mrow></math></span>. Let <span><math><mrow><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>=</mo><mi>α</mi><mi>D</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>+</mo><mrow><mo>(</mo><mn>1</mn><mo>−</mo><mi>α</mi><mo>)</mo></mrow><mi>A</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span>, where <span><math><mrow><mi>D</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> denotes the diagonal matrix of vertex degrees of <span><math><mi>G</mi></math></span> and <span><math><mrow><mi>A</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> denotes the adjacency matrix of <span><math><mi>G</mi></math></span>. The largest eigenvalue of <span><math><mrow><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> is called the <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius of <span><math><mi>G</mi></math></span>. In this paper, we explore the connections between the eigenvalues and the existence of a <span><math><mrow><mo>{</mo><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn><mi>i</mi><mo>+</mo><mn>1</mn></mrow></msub><mo>:</mo><mi>i</mi><mo>≥</mo><mn>1</mn><mo>}</mo></mrow></math></span>-factor in a graph. We derive a tight sufficient condition involving the <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius to ensure the existence of a <span><math><mrow><mo>{</mo><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn><mi>i</mi><mo>+</mo><mn>1</mn></mrow></msub><mo>:</mo><mi>i</mi><mo>≥</mo><mn>1</mn><mo>}</mo></mrow></math></span>-factor in a graph, which generalizes the result on <span><math><mrow><mi>α</mi><mo>=</mo><mn>0</mn></mrow></math></span> obtained by Chen, Lv and Li <span><span>[8]</span></span>. Moreover, we present a tight distance signless Laplacian spectral radius condition for the existence of a <span><math><mrow><mo>{</mo><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn><mi>i</mi><mo>+</mo><mn>1</mn></mrow></msub><mo>:</mo><mi>i</mi><mo>≥</mo><mn>1</mn><mo>}</mo></mrow></math></span>-factor in a graph.</p></div>","PeriodicalId":50573,"journal":{"name":"Discrete Applied Mathematics","volume":"360 ","pages":"Pages 81-92"},"PeriodicalIF":1.0000,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Some results on {K2,C2i+1:i≥1}-factor in a graph\",\"authors\":\"Xiaoyun Lv , Jianxi Li , Shou-Jun Xu\",\"doi\":\"10.1016/j.dam.2024.08.021\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>An <span><math><mrow><mo>{</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>,</mo><mo>…</mo><mo>}</mo></mrow></math></span>-factor of a graph <span><math><mi>G</mi></math></span> is defined to be a spanning subgraph of <span><math><mi>G</mi></math></span> such that each component of which is isomorphic to one of <span><math><mrow><mo>{</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>,</mo><mo>…</mo><mo>}</mo></mrow></math></span>. Let <span><math><mrow><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>=</mo><mi>α</mi><mi>D</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow><mo>+</mo><mrow><mo>(</mo><mn>1</mn><mo>−</mo><mi>α</mi><mo>)</mo></mrow><mi>A</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span>, where <span><math><mrow><mi>D</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> denotes the diagonal matrix of vertex degrees of <span><math><mi>G</mi></math></span> and <span><math><mrow><mi>A</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> denotes the adjacency matrix of <span><math><mi>G</mi></math></span>. The largest eigenvalue of <span><math><mrow><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> is called the <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius of <span><math><mi>G</mi></math></span>. In this paper, we explore the connections between the eigenvalues and the existence of a <span><math><mrow><mo>{</mo><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn><mi>i</mi><mo>+</mo><mn>1</mn></mrow></msub><mo>:</mo><mi>i</mi><mo>≥</mo><mn>1</mn><mo>}</mo></mrow></math></span>-factor in a graph. We derive a tight sufficient condition involving the <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius to ensure the existence of a <span><math><mrow><mo>{</mo><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn><mi>i</mi><mo>+</mo><mn>1</mn></mrow></msub><mo>:</mo><mi>i</mi><mo>≥</mo><mn>1</mn><mo>}</mo></mrow></math></span>-factor in a graph, which generalizes the result on <span><math><mrow><mi>α</mi><mo>=</mo><mn>0</mn></mrow></math></span> obtained by Chen, Lv and Li <span><span>[8]</span></span>. Moreover, we present a tight distance signless Laplacian spectral radius condition for the existence of a <span><math><mrow><mo>{</mo><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn><mi>i</mi><mo>+</mo><mn>1</mn></mrow></msub><mo>:</mo><mi>i</mi><mo>≥</mo><mn>1</mn><mo>}</mo></mrow></math></span>-factor in a graph.</p></div>\",\"PeriodicalId\":50573,\"journal\":{\"name\":\"Discrete Applied Mathematics\",\"volume\":\"360 \",\"pages\":\"Pages 81-92\"},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2024-09-06\",\"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/S0166218X24003792\",\"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/S0166218X24003792","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
图 G 的{A,B,C,...}因子定义为 G 的跨子图,其每个分量都与{A,B,C,...}中的一个分量同构。让 Aα(G)=αD(G)+(1-α)A(G),其中 D(G) 表示 G 的顶点度对角矩阵,A(G) 表示 G 的邻接矩阵。Aα(G) 的最大特征值称为 G 的 Aα 光谱半径。我们推导了一个涉及 Aα 谱半径的严密充分条件,以确保图中存在 {K2,C2i+1:i≥1}因子,这概括了 Chen、Lv 和 Li [8] 所得到的关于 α=0 的结果。此外,我们还提出了图中存在{K2,C2i+1:i≥1}因子的紧距无符号拉普拉斯谱半径条件。
An -factor of a graph is defined to be a spanning subgraph of such that each component of which is isomorphic to one of . Let , where denotes the diagonal matrix of vertex degrees of and denotes the adjacency matrix of . The largest eigenvalue of is called the -spectral radius of . In this paper, we explore the connections between the eigenvalues and the existence of a -factor in a graph. We derive a tight sufficient condition involving the -spectral radius to ensure the existence of a -factor in a graph, which generalizes the result on obtained by Chen, Lv and Li [8]. Moreover, we present a tight distance signless Laplacian spectral radius condition for the existence of a -factor in a graph.
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.