• Title/Summary/Keyword: Zagreb coindex

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CALCULATION OF SOME TOPOLOGICAL INDICES OF SPLICES AND LINKS OF GRAPHS

  • Ashra, Ali Reza;Hamzeh, Asma;Hossein-Zadeh, Samaneh
    • Journal of applied mathematics & informatics
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    • v.29 no.1_2
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    • pp.327-335
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    • 2011
  • Explicit formulas are given for the first and second Zagreb index, degree-distance and Wiener-type invariants of splice and link of graphs. As a consequence, the first and second Zagreb coindex of these classes of composite graphs are also computed.

REMARKS ON THE INNER POWER OF GRAPHS

  • JAFARI, S.;ASHRAFI, A.R.;FATH-TABAR, G.H.;TAVAKOLI, Mostafa
    • Journal of applied mathematics & informatics
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    • v.35 no.1_2
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    • pp.25-32
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    • 2017
  • Let G be a graph and k is a positive integer. Hammack and Livesay in [The inner power of a graph, Ars Math. Contemp., 3 (2010), no. 2, 193-199] introduced a new graph operation $G^{(k)}$, called the $k^{th}$ inner power of G. In this paper, it is proved that if G is bipartite then $G^{(2)}$ has exactly three components such that one of them is bipartite and two others are isomorphic. As a consequence the edge frustration index of $G^{(2)}$ is computed based on the same values as for the original graph G. We also compute the first and second Zagreb indices and coindices of $G^{(2)}$.