{"title":"通过修改总 σ-irregularity 来极化反规则图形","authors":"Martin Knor , Riste Škrekovski , Slobodan Filipovski , Darko Dimitrov","doi":"10.1016/j.amc.2024.129199","DOIUrl":null,"url":null,"abstract":"<div><div>The total <em>σ</em>-irregularity is given by <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><msub><mrow><mo>∑</mo></mrow><mrow><mo>{</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>}</mo><mo>⊆</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo></mrow></msub><msup><mrow><mo>(</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>u</mi><mo>)</mo><mo>−</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>v</mi><mo>)</mo><mo>)</mo></mrow><mrow><mn>2</mn></mrow></msup></math></span>, where <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>z</mi><mo>)</mo></math></span> indicates the degree of a vertex <em>z</em> within the graph <em>G</em>. It is known that the graphs maximizing <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span>-irregularity are split graphs with only a few distinct degrees. Since one might typically expect that graphs with as many distinct degrees as possible achieve maximum irregularity measures, we modify this invariant to <span><math><msubsup><mrow><mi>σ</mi></mrow><mrow><mi>t</mi></mrow><mrow><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><msub><mrow><mo>∑</mo></mrow><mrow><mo>{</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>}</mo><mo>⊆</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo></mrow></msub><mo>|</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>u</mi><mo>)</mo><mo>−</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>v</mi><mo>)</mo><msup><mrow><mo>|</mo></mrow><mrow><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo></mrow></msup></math></span>, where <span><math><mi>n</mi><mo>=</mo><mo>|</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo></math></span> and <span><math><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo><mo>></mo><mn>0</mn></math></span>. We study under what conditions the above modification obtains its maximum for antiregular graphs. We consider general graphs, trees, and chemical graphs, and accompany our results with a few problems and conjectures.</div></div>","PeriodicalId":55496,"journal":{"name":"Applied Mathematics and Computation","volume":"490 ","pages":"Article 129199"},"PeriodicalIF":3.5000,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Extremizing antiregular graphs by modifying total σ-irregularity\",\"authors\":\"Martin Knor , Riste Škrekovski , Slobodan Filipovski , Darko Dimitrov\",\"doi\":\"10.1016/j.amc.2024.129199\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The total <em>σ</em>-irregularity is given by <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><msub><mrow><mo>∑</mo></mrow><mrow><mo>{</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>}</mo><mo>⊆</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo></mrow></msub><msup><mrow><mo>(</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>u</mi><mo>)</mo><mo>−</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>v</mi><mo>)</mo><mo>)</mo></mrow><mrow><mn>2</mn></mrow></msup></math></span>, where <span><math><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>z</mi><mo>)</mo></math></span> indicates the degree of a vertex <em>z</em> within the graph <em>G</em>. It is known that the graphs maximizing <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span>-irregularity are split graphs with only a few distinct degrees. Since one might typically expect that graphs with as many distinct degrees as possible achieve maximum irregularity measures, we modify this invariant to <span><math><msubsup><mrow><mi>σ</mi></mrow><mrow><mi>t</mi></mrow><mrow><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo></mrow></msubsup><mo>(</mo><mi>G</mi><mo>)</mo><mo>=</mo><msub><mrow><mo>∑</mo></mrow><mrow><mo>{</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>}</mo><mo>⊆</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo></mrow></msub><mo>|</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>u</mi><mo>)</mo><mo>−</mo><msub><mrow><mi>d</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><mi>v</mi><mo>)</mo><msup><mrow><mo>|</mo></mrow><mrow><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo></mrow></msup></math></span>, where <span><math><mi>n</mi><mo>=</mo><mo>|</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo></math></span> and <span><math><mi>f</mi><mo>(</mo><mi>n</mi><mo>)</mo><mo>></mo><mn>0</mn></math></span>. We study under what conditions the above modification obtains its maximum for antiregular graphs. We consider general graphs, trees, and chemical graphs, and accompany our results with a few problems and conjectures.</div></div>\",\"PeriodicalId\":55496,\"journal\":{\"name\":\"Applied Mathematics and Computation\",\"volume\":\"490 \",\"pages\":\"Article 129199\"},\"PeriodicalIF\":3.5000,\"publicationDate\":\"2024-11-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Applied Mathematics and Computation\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S009630032400660X\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATHEMATICS, APPLIED\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Mathematics and Computation","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S009630032400660X","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS, APPLIED","Score":null,"Total":0}
引用次数: 0
摘要
σt(G)=∑{u,v}⊆V(G)(dG(u)-dG(v))2,其中 dG(z) 表示图 G 中顶点 z 的度数。由于人们通常希望具有尽可能多不同度数的图能达到最大不规则度,因此我们将此不变量修改为 σtf(n)(G)=∑{u,v}⊆V(G)|dG(u)-dG(v)|f(n), 其中 n=|V(G)| 且 f(n)>0.我们研究上述修正在什么条件下能获得反规则图的最大值。我们考虑了一般图、树图和化学图,并随结果提出了一些问题和猜想。
Extremizing antiregular graphs by modifying total σ-irregularity
The total σ-irregularity is given by , where indicates the degree of a vertex z within the graph G. It is known that the graphs maximizing -irregularity are split graphs with only a few distinct degrees. Since one might typically expect that graphs with as many distinct degrees as possible achieve maximum irregularity measures, we modify this invariant to , where and . We study under what conditions the above modification obtains its maximum for antiregular graphs. We consider general graphs, trees, and chemical graphs, and accompany our results with a few problems and conjectures.
期刊介绍:
Applied Mathematics and Computation addresses work at the interface between applied mathematics, numerical computation, and applications of systems – oriented ideas to the physical, biological, social, and behavioral sciences, and emphasizes papers of a computational nature focusing on new algorithms, their analysis and numerical results.
In addition to presenting research papers, Applied Mathematics and Computation publishes review articles and single–topics issues.