Štefko Miklavič , Johannes Pardey , Dieter Rautenbach , Florian Werner
{"title":"二部图和分裂图的Mostar指数最大化","authors":"Štefko Miklavič , Johannes Pardey , Dieter Rautenbach , Florian Werner","doi":"10.1016/j.disopt.2023.100768","DOIUrl":null,"url":null,"abstract":"<div><p>Došlić et al. defined the Mostar index of a graph <span><math><mi>G</mi></math></span> as <span><math><mrow><munder><mrow><mo>∑</mo></mrow><mrow><mi>u</mi><mi>v</mi><mo>∈</mo><mi>E</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></munder><mspace></mspace><mrow><mo>|</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>G</mi></mrow></msub><mrow><mo>(</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>)</mo></mrow><mo>−</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>G</mi></mrow></msub><mrow><mo>(</mo><mi>v</mi><mo>,</mo><mi>u</mi><mo>)</mo></mrow><mo>|</mo></mrow></mrow></math></span>, where, for an edge <span><math><mrow><mi>u</mi><mi>v</mi></mrow></math></span> of <span><math><mi>G</mi></math></span>, the term <span><math><mrow><msub><mrow><mi>n</mi></mrow><mrow><mi>G</mi></mrow></msub><mrow><mo>(</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>)</mo></mrow></mrow></math></span> denotes the number of vertices of <span><math><mi>G</mi></math></span> that have a smaller distance in <span><math><mi>G</mi></math></span> to <span><math><mi>u</mi></math></span> than to <span><math><mi>v</mi></math></span><span>. Contributing to conjectures posed by Došlić et al., we show that the Mostar index of bipartite graphs of order </span><span><math><mi>n</mi></math></span> is at most <span><math><mrow><mfrac><mrow><msqrt><mrow><mn>3</mn></mrow></msqrt></mrow><mrow><mn>18</mn></mrow></mfrac><msup><mrow><mi>n</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math></span>, and that the Mostar index of split graphs of order <span><math><mi>n</mi></math></span> is at most <span><math><mrow><mfrac><mrow><mn>4</mn></mrow><mrow><mn>27</mn></mrow></mfrac><msup><mrow><mi>n</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math></span>.</p></div>","PeriodicalId":50571,"journal":{"name":"Discrete Optimization","volume":null,"pages":null},"PeriodicalIF":0.9000,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"4","resultStr":"{\"title\":\"Maximizing the Mostar index for bipartite graphs and split graphs\",\"authors\":\"Štefko Miklavič , Johannes Pardey , Dieter Rautenbach , Florian Werner\",\"doi\":\"10.1016/j.disopt.2023.100768\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Došlić et al. defined the Mostar index of a graph <span><math><mi>G</mi></math></span> as <span><math><mrow><munder><mrow><mo>∑</mo></mrow><mrow><mi>u</mi><mi>v</mi><mo>∈</mo><mi>E</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></munder><mspace></mspace><mrow><mo>|</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>G</mi></mrow></msub><mrow><mo>(</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>)</mo></mrow><mo>−</mo><msub><mrow><mi>n</mi></mrow><mrow><mi>G</mi></mrow></msub><mrow><mo>(</mo><mi>v</mi><mo>,</mo><mi>u</mi><mo>)</mo></mrow><mo>|</mo></mrow></mrow></math></span>, where, for an edge <span><math><mrow><mi>u</mi><mi>v</mi></mrow></math></span> of <span><math><mi>G</mi></math></span>, the term <span><math><mrow><msub><mrow><mi>n</mi></mrow><mrow><mi>G</mi></mrow></msub><mrow><mo>(</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>)</mo></mrow></mrow></math></span> denotes the number of vertices of <span><math><mi>G</mi></math></span> that have a smaller distance in <span><math><mi>G</mi></math></span> to <span><math><mi>u</mi></math></span> than to <span><math><mi>v</mi></math></span><span>. Contributing to conjectures posed by Došlić et al., we show that the Mostar index of bipartite graphs of order </span><span><math><mi>n</mi></math></span> is at most <span><math><mrow><mfrac><mrow><msqrt><mrow><mn>3</mn></mrow></msqrt></mrow><mrow><mn>18</mn></mrow></mfrac><msup><mrow><mi>n</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math></span>, and that the Mostar index of split graphs of order <span><math><mi>n</mi></math></span> is at most <span><math><mrow><mfrac><mrow><mn>4</mn></mrow><mrow><mn>27</mn></mrow></mfrac><msup><mrow><mi>n</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math></span>.</p></div>\",\"PeriodicalId\":50571,\"journal\":{\"name\":\"Discrete Optimization\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.9000,\"publicationDate\":\"2023-05-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"4\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Discrete Optimization\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1572528623000105\",\"RegionNum\":4,\"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 Optimization","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1572528623000105","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS, APPLIED","Score":null,"Total":0}
Maximizing the Mostar index for bipartite graphs and split graphs
Došlić et al. defined the Mostar index of a graph as , where, for an edge of , the term denotes the number of vertices of that have a smaller distance in to than to . Contributing to conjectures posed by Došlić et al., we show that the Mostar index of bipartite graphs of order is at most , and that the Mostar index of split graphs of order is at most .
期刊介绍:
Discrete Optimization publishes research papers on the mathematical, computational and applied aspects of all areas of integer programming and combinatorial optimization. In addition to reports on mathematical results pertinent to discrete optimization, the journal welcomes submissions on algorithmic developments, computational experiments, and novel applications (in particular, large-scale and real-time applications). The journal also publishes clearly labelled surveys, reviews, short notes, and open problems. Manuscripts submitted for possible publication to Discrete Optimization should report on original research, should not have been previously published, and should not be under consideration for publication by any other journal.