Cactus Graphs with Maximal Multiplicative Sum Zagreb Index

A connected graph <i>G</i> is said to be a cactus if any two cycles have at most one vertex in common. The multiplicative sum Zagreb index of a graph <i>G</i> is the product of the sum of the degrees of adjacent vertices in <i>G</i>. In this paper, we introduce se...

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Main Authors: Chunlei Xu, Batmend Horoldagva, Lkhagva Buyantogtokh
Format: Article
Language:English
Published: MDPI AG 2021-05-01
Series:Symmetry
Subjects:
Online Access:https://www.mdpi.com/2073-8994/13/5/913
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author Chunlei Xu
Batmend Horoldagva
Lkhagva Buyantogtokh
author_facet Chunlei Xu
Batmend Horoldagva
Lkhagva Buyantogtokh
author_sort Chunlei Xu
collection DOAJ
description A connected graph <i>G</i> is said to be a cactus if any two cycles have at most one vertex in common. The multiplicative sum Zagreb index of a graph <i>G</i> is the product of the sum of the degrees of adjacent vertices in <i>G</i>. In this paper, we introduce several graph transformations that are useful tools for the study of the extremal properties of the multiplicative sum Zagreb index. Using these transformations and symmetric structural representations of some cactus graphs, we determine the graphs having maximal multiplicative sum Zagreb index for cactus graphs with the prescribed number of pendant vertices (cut edges). Furthermore, the graphs with maximal multiplicative sum Zagreb index are characterized among all cactus graphs of the given order.
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spelling doaj.art-95412a0e812a482a9ef816fdf77c862a2023-11-21T20:37:27ZengMDPI AGSymmetry2073-89942021-05-0113591310.3390/sym13050913Cactus Graphs with Maximal Multiplicative Sum Zagreb IndexChunlei Xu0Batmend Horoldagva1Lkhagva Buyantogtokh2Department of Mathematics, Mongolian National University of Education, Baga toiruu-14, Ulaanbaatar 210648, MongoliaDepartment of Mathematics, Mongolian National University of Education, Baga toiruu-14, Ulaanbaatar 210648, MongoliaDepartment of Mathematics, Mongolian National University of Education, Baga toiruu-14, Ulaanbaatar 210648, MongoliaA connected graph <i>G</i> is said to be a cactus if any two cycles have at most one vertex in common. The multiplicative sum Zagreb index of a graph <i>G</i> is the product of the sum of the degrees of adjacent vertices in <i>G</i>. In this paper, we introduce several graph transformations that are useful tools for the study of the extremal properties of the multiplicative sum Zagreb index. Using these transformations and symmetric structural representations of some cactus graphs, we determine the graphs having maximal multiplicative sum Zagreb index for cactus graphs with the prescribed number of pendant vertices (cut edges). Furthermore, the graphs with maximal multiplicative sum Zagreb index are characterized among all cactus graphs of the given order.https://www.mdpi.com/2073-8994/13/5/913multiplicative sum Zagreb indexcactus graphpendant vertexcut edge
spellingShingle Chunlei Xu
Batmend Horoldagva
Lkhagva Buyantogtokh
Cactus Graphs with Maximal Multiplicative Sum Zagreb Index
Symmetry
multiplicative sum Zagreb index
cactus graph
pendant vertex
cut edge
title Cactus Graphs with Maximal Multiplicative Sum Zagreb Index
title_full Cactus Graphs with Maximal Multiplicative Sum Zagreb Index
title_fullStr Cactus Graphs with Maximal Multiplicative Sum Zagreb Index
title_full_unstemmed Cactus Graphs with Maximal Multiplicative Sum Zagreb Index
title_short Cactus Graphs with Maximal Multiplicative Sum Zagreb Index
title_sort cactus graphs with maximal multiplicative sum zagreb index
topic multiplicative sum Zagreb index
cactus graph
pendant vertex
cut edge
url https://www.mdpi.com/2073-8994/13/5/913
work_keys_str_mv AT chunleixu cactusgraphswithmaximalmultiplicativesumzagrebindex
AT batmendhoroldagva cactusgraphswithmaximalmultiplicativesumzagrebindex
AT lkhagvabuyantogtokh cactusgraphswithmaximalmultiplicativesumzagrebindex