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Zagreb indices of subgroup generating bipartite graph

Group Theory 2025-01-13 v1

Abstract

Let GG be a group and L(G)L(G) be the set of all subgroups of GG. The subgroup generating bipartite graph B(G)\mathcal{B}(G) defined on GG is a bipartite graph whose vertex set is partitioned into two sets G×GG \times G and L(G)L(G), and two vertices (a,b)G×G(a, b) \in G \times G and HL(G)H \in L(G) are adjacent if HH is generated by aa and bb. In this paper, we deduce expressions for first and second Zagreb indices of B(G)\mathcal{B}(G) and obtain a condition such that B(G)\mathcal{B}(G) satisfy Hansen-Vuki{\v{c}}evi{\'c} conjecture [Hansen, P. and Vuki{\v{c}}evi{\'c}, D. Comparing the Zagreb indices, {\em Croatica Chemica Acta}, \textbf{80}(2), 165-168, 2007]. It is shown that B(G)\mathcal{B}(G) satisfies Hansen-Vuki{\v{c}}evi{\'c} conjecture if GG is a cyclic group of order 2p,2p2,4p2p, 2p^2, 4p, 4p24p^2 and pnp^n; dihedral group of order 2p2p and 2p22p^2; and dicyclic group of order 4p4p and 4p24p^2 for any prime pp. While computing Zagreb indices of B(G)\mathcal{B}(G) we have computed degB(G)(H)\deg_{\mathcal{B}(G)}(H) for all HL(G)H \in L(G) for the above mentioned groups. Using these information we also compute Randic Connectivity index, Atom-Bond Connectivity index, Geometric-Arithmetic index, Harmonic index and Sum-Connectivity index of B(G)\mathcal{B}(G).

Keywords

Cite

@article{arxiv.2501.06124,
  title  = {Zagreb indices of subgroup generating bipartite graph},
  author = {Shrabani Das and Ahmad Erfanian and Rajat Kanti Nath},
  journal= {arXiv preprint arXiv:2501.06124},
  year   = {2025}
}

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17 pages