{"title":"A method for constructing graphs with the same resistance spectrum","authors":"","doi":"10.1016/j.disc.2024.114284","DOIUrl":null,"url":null,"abstract":"<div><div>Let <em>G</em> be a simple graph with vertex set <span><math><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> and edge set <span><math><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span>. The resistance distance <span><math><msub><mrow><mi>R</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo>)</mo></math></span> between two vertices <span><math><mi>x</mi><mo>,</mo><mi>y</mi></math></span> of <em>G</em>, is defined to be the effective resistance between the two vertices in the corresponding electrical network in which each edge of <em>G</em> is replaced by a unit resistor. The resistance spectrum <span><math><mi>RS</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> of a graph <em>G</em> is the multiset of the resistance distances between all pairs of vertices in the graph. This paper presents a novel method for constructing graphs with the same resistance spectrum. It is obtained that for any positive integer <em>k</em>, there exist at least <span><math><msup><mrow><mn>2</mn></mrow><mrow><mi>k</mi></mrow></msup></math></span> graphs with the same resistance spectrum. Furthermore, it is shown that for <span><math><mi>n</mi><mo>≥</mo><mn>10</mn></math></span>, there are at least <span><math><mn>2</mn><mo>(</mo><mo>(</mo><mi>n</mi><mo>−</mo><mn>10</mn><mo>)</mo><mi>p</mi><mo>(</mo><mi>n</mi><mo>−</mo><mn>9</mn><mo>)</mo><mo>+</mo><mi>q</mi><mo>(</mo><mi>n</mi><mo>−</mo><mn>9</mn><mo>)</mo><mo>)</mo></math></span> pairs of graphs of order <em>n</em> with the same resistance spectrum, where <span><math><mi>p</mi><mo>(</mo><mi>n</mi><mo>−</mo><mn>9</mn><mo>)</mo></math></span> and <span><math><mi>q</mi><mo>(</mo><mi>n</mi><mo>−</mo><mn>9</mn><mo>)</mo></math></span> are the numbers of partitions of the integer <span><math><mi>n</mi><mo>−</mo><mn>9</mn></math></span> and simple graphs of order <span><math><mi>n</mi><mo>−</mo><mn>9</mn></math></span>, respectively.</div></div>","PeriodicalId":50572,"journal":{"name":"Discrete Mathematics","volume":null,"pages":null},"PeriodicalIF":0.7000,"publicationDate":"2024-10-14","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/S0012365X24004151","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
Abstract
Let G be a simple graph with vertex set and edge set . The resistance distance between two vertices of G, is defined to be the effective resistance between the two vertices in the corresponding electrical network in which each edge of G is replaced by a unit resistor. The resistance spectrum of a graph G is the multiset of the resistance distances between all pairs of vertices in the graph. This paper presents a novel method for constructing graphs with the same resistance spectrum. It is obtained that for any positive integer k, there exist at least graphs with the same resistance spectrum. Furthermore, it is shown that for , there are at least pairs of graphs of order n with the same resistance spectrum, where and are the numbers of partitions of the integer and simple graphs of order , respectively.
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.