星形分支树和花束分支图的(Af)α-谱半径与其线性阶数的关系

IF 0.7 3区 数学 Q2 MATHEMATICS
Xueliang Li, Ruiling Zheng
{"title":"星形分支树和花束分支图的(Af)α-谱半径与其线性阶数的关系","authors":"Xueliang Li,&nbsp;Ruiling Zheng","doi":"10.1016/j.disc.2025.114734","DOIUrl":null,"url":null,"abstract":"<div><div>For a graph <em>G</em> and a vertex <em>v</em> of <em>G</em>, let <span><math><msub><mrow><mi>G</mi></mrow><mrow><mi>v</mi></mrow></msub><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></math></span> be the graph obtained from <em>G</em> by linking the paths on <span><math><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span> vertices to the vertex <em>v</em> of <em>G</em>, respectively. We denote by <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></math></span> (or <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> for short) the degree of the vertex <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> in <em>G</em>. Let <span><math><mi>f</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo><mo>&gt;</mo><mn>0</mn></math></span> be a real symmetric function in <em>x</em> and <em>y</em>. The function-weighted adjacency matrix <span><math><msup><mrow><mi>A</mi></mrow><mrow><mi>f</mi></mrow></msup><mo>(</mo><mi>G</mi><mo>)</mo></math></span> of a graph <em>G</em> is a square matrix, where the <span><math><mo>(</mo><mi>i</mi><mo>,</mo><mi>j</mi><mo>)</mo></math></span>-entry is equal to <span><math><mi>f</mi><mo>(</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>,</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>)</mo></math></span> if the vertices <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>j</mi></mrow></msub></math></span> are adjacent and 0 otherwise, in which <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> is the degree of the vertex <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>. In <span><span>[22]</span></span>, Shan and Liu showed that the <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius of <span><math><msub><mrow><mi>G</mi></mrow><mrow><mi>v</mi></mrow></msub><mrow><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></mrow></math></span> will increase according to the shortlex ordering of <span><math><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></math></span>. However, we find some mistakes in their proof. In this paper, we will correct their proof, and moreover, extend their results from the <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius to the <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>A</mi></mrow><mrow><mi>f</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius. In addition, let <span><math><msubsup><mrow><mi>G</mi></mrow><mrow><mi>v</mi></mrow><mrow><mi>c</mi></mrow></msubsup><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></math></span> be the graph obtained from <em>G</em> by identifying a vertex from each of the cycles on <span><math><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span> vertices and the vertex <em>v</em> of <em>G</em>, respectively. We will show that the <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>A</mi></mrow><mrow><mi>f</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius of <span><math><msubsup><mrow><mi>G</mi></mrow><mrow><mi>v</mi></mrow><mrow><mi>c</mi></mrow></msubsup><mrow><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></mrow></math></span> will decrease according to the majorization ordering of <span><math><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></math></span>.</div></div>","PeriodicalId":50572,"journal":{"name":"Discrete Mathematics","volume":"349 1","pages":"Article 114734"},"PeriodicalIF":0.7000,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On the relationship between (Af)α-spectral radii of graphs with starlike branch tree or bouquet branch graph and its linearly order\",\"authors\":\"Xueliang Li,&nbsp;Ruiling Zheng\",\"doi\":\"10.1016/j.disc.2025.114734\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>For a graph <em>G</em> and a vertex <em>v</em> of <em>G</em>, let <span><math><msub><mrow><mi>G</mi></mrow><mrow><mi>v</mi></mrow></msub><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></math></span> be the graph obtained from <em>G</em> by linking the paths on <span><math><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span> vertices to the vertex <em>v</em> of <em>G</em>, respectively. We denote by <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></math></span> (or <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> for short) the degree of the vertex <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> in <em>G</em>. Let <span><math><mi>f</mi><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo><mo>&gt;</mo><mn>0</mn></math></span> be a real symmetric function in <em>x</em> and <em>y</em>. The function-weighted adjacency matrix <span><math><msup><mrow><mi>A</mi></mrow><mrow><mi>f</mi></mrow></msup><mo>(</mo><mi>G</mi><mo>)</mo></math></span> of a graph <em>G</em> is a square matrix, where the <span><math><mo>(</mo><mi>i</mi><mo>,</mo><mi>j</mi><mo>)</mo></math></span>-entry is equal to <span><math><mi>f</mi><mo>(</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>,</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>)</mo></math></span> if the vertices <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>j</mi></mrow></msub></math></span> are adjacent and 0 otherwise, in which <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> is the degree of the vertex <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>. In <span><span>[22]</span></span>, Shan and Liu showed that the <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius of <span><math><msub><mrow><mi>G</mi></mrow><mrow><mi>v</mi></mrow></msub><mrow><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></mrow></math></span> will increase according to the shortlex ordering of <span><math><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></math></span>. However, we find some mistakes in their proof. In this paper, we will correct their proof, and moreover, extend their results from the <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius to the <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>A</mi></mrow><mrow><mi>f</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius. In addition, let <span><math><msubsup><mrow><mi>G</mi></mrow><mrow><mi>v</mi></mrow><mrow><mi>c</mi></mrow></msubsup><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></math></span> be the graph obtained from <em>G</em> by identifying a vertex from each of the cycles on <span><math><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span> vertices and the vertex <em>v</em> of <em>G</em>, respectively. We will show that the <span><math><msub><mrow><mo>(</mo><msup><mrow><mi>A</mi></mrow><mrow><mi>f</mi></mrow></msup><mo>)</mo></mrow><mrow><mi>α</mi></mrow></msub></math></span>-spectral radius of <span><math><msubsup><mrow><mi>G</mi></mrow><mrow><mi>v</mi></mrow><mrow><mi>c</mi></mrow></msubsup><mrow><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></mrow></math></span> will decrease according to the majorization ordering of <span><math><mo>(</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo></math></span>.</div></div>\",\"PeriodicalId\":50572,\"journal\":{\"name\":\"Discrete Mathematics\",\"volume\":\"349 1\",\"pages\":\"Article 114734\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2025-08-22\",\"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/S0012365X25003425\",\"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/S0012365X25003425","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

对于图G和G的顶点v,设Gv(n1,n2,…,nd)为将n1,n2,…,和顶点上的路径分别连接到G的顶点v而得到的图。我们表示dG (vi)(简称di)顶点的度六世在G .让f (x, y)在0 x和y是一个实对称函数。function-weighted邻接矩阵Af (G)的图G是一个方阵,在(i, j)进口= f (di, dj)如果顶点0 vi和vj相邻,否则,di的顶点的度vi。[22],掸族和刘表明α谱半径的全球之声(n1、n2…,nd)将增加的shortlex订购(n1、n2…,nd)。然而,我们在他们的证明中发现了一些错误。本文对他们的证明进行了修正,并将他们的结果从a α-谱半径推广到(Af)α-谱半径。另外,设Gvc(n1,n2,…,nd)为从G的n1,n2,…,和顶点上的每个循环中分别识别一个顶点和G的顶点v而得到的图。我们将证明Gvc(n1,n2,…,nd)的(Af)α-谱半径会按照(n1,n2,…,nd)的多数化顺序减小。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
On the relationship between (Af)α-spectral radii of graphs with starlike branch tree or bouquet branch graph and its linearly order
For a graph G and a vertex v of G, let Gv(n1,n2,,nd) be the graph obtained from G by linking the paths on n1,n2,,nd vertices to the vertex v of G, respectively. We denote by dG(vi) (or di for short) the degree of the vertex vi in G. Let f(x,y)>0 be a real symmetric function in x and y. The function-weighted adjacency matrix Af(G) of a graph G is a square matrix, where the (i,j)-entry is equal to f(di,dj) if the vertices vi and vj are adjacent and 0 otherwise, in which di is the degree of the vertex vi. In [22], Shan and Liu showed that the Aα-spectral radius of Gv(n1,n2,,nd) will increase according to the shortlex ordering of (n1,n2,,nd). However, we find some mistakes in their proof. In this paper, we will correct their proof, and moreover, extend their results from the Aα-spectral radius to the (Af)α-spectral radius. In addition, let Gvc(n1,n2,,nd) be the graph obtained from G by identifying a vertex from each of the cycles on n1,n2,,nd vertices and the vertex v of G, respectively. We will show that the (Af)α-spectral radius of Gvc(n1,n2,,nd) will decrease according to the majorization ordering of (n1,n2,,nd).
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来源期刊
Discrete Mathematics
Discrete Mathematics 数学-数学
CiteScore
1.50
自引率
12.50%
发文量
424
审稿时长
6 months
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.
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