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Open Access Research Article

Extremal unicyclic graphs with fixed leaves via Sombor index

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pp. 783–795Vol. 28Issue 3April 2025DOI: 10.47974/JDMSC-1988 Crossmark XML
Received:
11 Oct 2023
Published Online:
18 Dec 2024
Article type:
Research Article
Language:
EN
Article no.:
JDMSC-1988
Pages:
783–795

Abstract

Gutman presented the Sombor index in 2021 as a topological molecular descriptor defined by graph A =  Sa1a2 ∈ E(A)√β(a1)2 + β(a1)2,  where β(a1) is the degree of the vertex a1 ∈ A. A connected graph is said to be unicyclic graph if it has same order and size. In this paper, we characterize the extremal graphs with respect to Sombor index in the class of unicyclic graphs having fixed leaves (nodes with degree one) associated with extremal graphs. Moreover, we compute the bounds on Sombor index in the same class of graphs.

Keywords

Subject Classifications

05C1005C3505C6205C12

References

[1] P. G. Seybold, M. May, and U. A. Bagal, “Molecular-structure property relationship,” J. Chem. Educ., vol. 64, pp. 575-581 (1987).
[2] A. T. Balaban, “Applications of graph theory in chemistry,” J. Chem. Inf. Comput. Sci., vol. 25, no. 3, pp. 334-343 (1985).
[3] A. T. Balaban, Ed., Chemical Applications of Graph Theory. London, U.K. Academic Press (1976).
[4] J. R. Dias and G. W. A. Milne, “Chemical applications of graph theory,” J. Chem. Inf. Comput. Sci., vol. 32, no. 1, pp. 210-242 (1992).
[5] P. J. Hansen and P. C. Jurs, “Chemical applications of graph theory. Part I. Fundamentals and topological indices,” J. Chem. Educ., vol. 65, pp. 574-580 (1988).
[6] H.Wiener, “Structural determination of paraffin boiling points,” J. Am. Chem. Soc., vol. 69, pp. 17-20 (1947).
[7] I. Gutman, “Degree-based topological indices,” Croat. Chem. Acta, vol. 86, pp. 351-361 (2013). 
[8] D. B. West, Introduction to Graph Theory. USA: Prentice Hall (1996).
[9] I. Gutman and N. Trinajstic, “Graph theory and molecular orbitals: Total -electron energy of alternant hydrocarbons,” Chem. Phys. Lett., vol. 17, pp. 535-538 (1972).
[10] B. Furtula, A. Graovac, and D. Vukicevic, “Augmented Zagreb index,” Journal of Mathematical Chemistry, vol. 48, pp. 370-380 (2010).
[11] R. Todeschini and V. Consonni, Molecular Descriptors for Chemoinformatics: Volume I: Alphabetical Listing Volume II: Appendices, References, vol. 41. John Wiley and Sons (2009).
[12] E. Estrada, L. Torres, L. Rodriguez, and I. Gutman, “An atom-bond connectivity index: Modelling the enthalpy of formation of alkanes,”  (1998).
[13] M. Ghorbani and M. A. Hosseinzadeh, “Computing ABC4 index of nanostar dendrimers,” Journal of Mathematical Chemistry, vol. 4, pp. 1419-1422, Sep. (2010).
[14] A. Ali, I. Gutman, E. Milovanovic, and I. Milovanovic, “Sum of powers of the degrees of graphs: Extremal results and bounds,” MATCH Commun. Math. Comput. Chem., vol. 80, pp. 5-84 (2018).
[15] A. Ali, L. Zhong, and I. Gutman, “Harmonic index and its generalizations: Extremal results and bounds,” MATCH Commun. Math. Comput. Chem., vol. 81, pp. 249-311 (2019).
[16] A. Sattar, M. Javaid, and M. A. Ashebo, “On the comparative analysis among topological indices for rhombus silicate and oxide structures,” Journal of Mathematics, vol. 2024, no. 1, pp. 2773913 (2024).
[17] B. Borovicanin, K. C. Das, B. Furtula, and I. Gutman, “Bounds for Zagreb indices,” MATCH Commun. Math. Comput. Chem., vol. 78, pp. 17-100 (2017).
[18] M. Javaid, A. Sattar, and E. Bonyah, “Topological aspects of molecular networks: crystal cubic carbons,” Complexity, vol. 2022, no. 1, pp. 3458094 (2022).
[19] I. Gutman, “Geometric approach to degree-based topological indices: Sombor indices,” MATCH Commun. Math. Comput. Chem., vol. 86, pp. 11-16 (2021).
[20] H. Chen, W. Li, and J. Wang, “Extremal values on the Sombor index of trees,” MATCH Commun. Math. Comput. Chem., vol. 87, pp. 87 (2022).
[21] H. Liu, “Extremal problems on Sombor indices of unicyclic graphs with a given diameter,” Comput. Appl. Math., vol. 41, no. 4, pp. 1-11 (2022).
[22] T. Zhou, Z. Lin, and L. Miao, “The extremal Sombor index of trees and unicyclic graphs with given matching number,” Journal of Discrete Mathematical Sciences and Cryptography, pp. 1-12 (2022).
[23] R. Cruz and J. Rada, “Extremal values of the Sombor index in unicyclic and bicyclic graphs,” J. Math. Chem., vol. 59, no. 4, pp. 1098-1116 (2021).
[24] M. Javaid, M. Ahmad, M. Hussain, and W. C. Teh, “Bounds of F-index for unicyclic graphs with fixed pendent vertices,” J. Prime Res. Math., vol. 14, pp. 51-61 (2018).
[25] S. Akram, M. Javaid, and M. Jamal, “Bounds on F-index of tricyclic graphs with fixed pendant vertices,” Open Mathematics, vol. 18, no. 1, pp. 150-161 (2020).
[26] R. Cruz, I. Gutman, and J. Rada, “Sombor index of chemical graphs,” Appl. Math. Comput., vol. 399, pp. 126018 (2021).
[27] H. Deng, Z. Tang, and R.Wu, “Molecular trees with extremal values of Sombor indices,” Int. J. Quantum Chem., vol. 121, pp. 26622 (2021).
[28] X. Fang, L. You, and H. Liu, “The expected values of Sombor indices in random hexagonal chains, phenylene chains and Sombor indices of some chemical graphs,” Int. J. Quantum Chem., vol. 121, pp.26740 (2021).
[29] I. Gutman, “Some basic properties of Sombor indices,” Open J. Discr. Appl. Math., vol. 4, pp. 1-3 (2021).
[30] D. Vukicevic and B. Furtula, “Topological index based on the ratios of geometrical and arithmetical means of end-vertex degrees of edges,” J. Math. Chem., vol. 46, no. 4, pp. 1369-1376 (2009).
[31] A. Arshad, A. Sattar, M. Javaid, and M. Abebe Ashebo, “Connection number-based topological indices of Cartesian product of graphs,” Journal of Mathematics, vol. 2023, no. 1, pp. 8272936 (2023).

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