Snježana Majstorović, Martin Knor, Riste Škrekovski
{"title":"Graphs preserving total distance upon vertex removal","authors":"Snježana Majstorović, Martin Knor, Riste Škrekovski","doi":"10.1016/j.endm.2018.06.019","DOIUrl":null,"url":null,"abstract":"<div><p>The total distance or Wiener index <span><math><mi>W</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> of a connected graph <em>G</em> is defined as the sum of distances between all pairs of vertices in <em>G</em>. In 1991, Šoltés posed the problem of finding all graphs <em>G</em> such that the equality <span><math><mi>W</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><mi>W</mi><mo>(</mo><mi>G</mi><mo>−</mo><mi>v</mi><mo>)</mo></math></span> holds for all their vertices <em>v</em>. Up to now, the only known graph with this property is the cycle <em>C</em><sub>11</sub>. Our main object of study is a relaxed version of this problem: Find graphs for which total distance does not change when a particular vertex is removed. We show that there are infinitely many graphs that satisfy this property. This gives hope that Šoltes's problem may have also some solutions distinct from <em>C</em><sub>11</sub>.</p></div>","PeriodicalId":35408,"journal":{"name":"Electronic Notes in Discrete Mathematics","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2018-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.endm.2018.06.019","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Electronic Notes in Discrete Mathematics","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1571065318301100","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"Mathematics","Score":null,"Total":0}
引用次数: 1
Abstract
The total distance or Wiener index of a connected graph G is defined as the sum of distances between all pairs of vertices in G. In 1991, Šoltés posed the problem of finding all graphs G such that the equality holds for all their vertices v. Up to now, the only known graph with this property is the cycle C11. Our main object of study is a relaxed version of this problem: Find graphs for which total distance does not change when a particular vertex is removed. We show that there are infinitely many graphs that satisfy this property. This gives hope that Šoltes's problem may have also some solutions distinct from C11.
期刊介绍:
Electronic Notes in Discrete Mathematics is a venue for the rapid electronic publication of the proceedings of conferences, of lecture notes, monographs and other similar material for which quick publication is appropriate. Organizers of conferences whose proceedings appear in Electronic Notes in Discrete Mathematics, and authors of other material appearing as a volume in the series are allowed to make hard copies of the relevant volume for limited distribution. For example, conference proceedings may be distributed to participants at the meeting, and lecture notes can be distributed to those taking a course based on the material in the volume.