For a $ \nu $-vertex connected graph $ \Gamma $, we consider the reciprocal distance Laplacian matrix defined as $ RD^L(\Gamma) = RT(\Gamma)-RD(\Gamma) $, i.e., $ RD^L(\Gamma) $ is the difference between the diagonal matrix of the reciprocal distance degrees $ RT(\Gamma) $ and the Harary matrix $ RD(\Gamma) $. In this article, we determine the graphs with exactly two distinct reciprocal distance Laplacian eigenvalues.We completely characterize the graph classes with a $ RD^L $ eigenvalue of multiplicity $ \nu-2 $. Moreover, we characterize families of graphs with reciprocal distance Laplacian eigenvalue whose multiplicity is $ \nu-3 $.
Citation: Milica Anđelić, Saleem Khan, S. Pirzada. On graphs with a few distinct reciprocal distance Laplacian eigenvalues[J]. AIMS Mathematics, 2023, 8(12): 29008-29016. doi: 10.3934/math.20231485
For a $ \nu $-vertex connected graph $ \Gamma $, we consider the reciprocal distance Laplacian matrix defined as $ RD^L(\Gamma) = RT(\Gamma)-RD(\Gamma) $, i.e., $ RD^L(\Gamma) $ is the difference between the diagonal matrix of the reciprocal distance degrees $ RT(\Gamma) $ and the Harary matrix $ RD(\Gamma) $. In this article, we determine the graphs with exactly two distinct reciprocal distance Laplacian eigenvalues.We completely characterize the graph classes with a $ RD^L $ eigenvalue of multiplicity $ \nu-2 $. Moreover, we characterize families of graphs with reciprocal distance Laplacian eigenvalue whose multiplicity is $ \nu-3 $.
[1] | D. Plavšić, S. Nikolić, N. Trinajstić, Z. Mihalić, On the Harary index for the characterization of chemical graphs, J. Math. Chem., 12 (1993), 235–250. https://doi.org/10.1007/BF01164638 doi: 10.1007/BF01164638 |
[2] | K. C. Das, Maximum eigenvalue of the reciprocal distance matrix, J. Math. Chem., 47 (2010), 21–28. https://doi.org/10.1007/s10910-009-9529-1 doi: 10.1007/s10910-009-9529-1 |
[3] | F. Huang, X. Li, S. Wang, On graphs with maximum Harary spectral radius, Appl. Math. Comput., 266 (2014), 937–945. https://doi.org/10.1016/j.amc.2015.05.146 doi: 10.1016/j.amc.2015.05.146 |
[4] | B. Zhou, N. Trinajstić, Maximum eigenvalues of the reciprocal distance matrix and the reverse Wiener matrix, Int. J. Quantum Chem., 108 (2008), 858–864. https://doi.org/10.1002/qua.21558 doi: 10.1002/qua.21558 |
[5] | R. Bapat, S. K. Panda, The spectral radius of the Reciprocal distance Laplacian matrix of a graph, B. Iran. Math. Soc., 44 (2018), 1211–1216. https://doi.org/10.1007/s41980-018-0084-z doi: 10.1007/s41980-018-0084-z |
[6] | S. Pirzada, S. Khan, On the distribution of eigenvalues of the reciprocal distance Laplacian matrix of graphs, Filomat, 37 (2023), 7973–7980. |
[7] | L. Medina, M. Trigo, Upper bounds and lower bounds for the spectral radius of reciprocal distance, reciprocal distance Laplacian and reciprocal distance signless Laplacian matrices, Linear Algebra Appl., 609 (2021), 386–412. https://doi.org/10.1016/j.laa.2020.09.024 doi: 10.1016/j.laa.2020.09.024 |
[8] | L. Medina, M. Trigo, Bounds on the reciprocal distance energy and reciprocal distance Laplacian energies of a graph, Linear Multilinear A., 70 (2022), 3097–3118. https://doi.org/10.1080/03081087.2020.1825607 doi: 10.1080/03081087.2020.1825607 |
[9] | M. Trigo, On Hararay energy and reciprocal distance Laplacian energies, J. Phys. Conf. Ser., 2090 (2021), 012102. https://doi.org/10.1088/1742-6596/2090/1/012102 doi: 10.1088/1742-6596/2090/1/012102 |
[10] | S. Pirzada, An introduction to graph theory, Hyderabad: Universities Press, 2012. |
[11] | D. Corneil, H. Lerchs, L. Burlingham, Complement reducible graphs, Discrete Appl. Math., 3 (1981), 163–174. https://doi.org/10.1016/0166-218X(81)90013-5 |
[12] | R. Fernandes, M. Aguieiras, A. Freitas, C. M. Silva, R. R. D. Vecchio, Multiplicities of distance Laplacian eigenvalues and forbidden subgraphs, Linear Algebra Appl., 541 (2018), 81–93. https://doi.org/10.1016/j.laa.2017.11.031 doi: 10.1016/j.laa.2017.11.031 |
[13] | K. C. Das, A sharp upper bound for the number of spanning trees of a graph, Graphs Combin., 23 (2007), 625–632. https://doi.org/10.1007/s00373-007-0758-4 doi: 10.1007/s00373-007-0758-4 |
[14] | R. Merris, Laplacian eigenvalues of graphs: A survey, Linear Algebra Appl., 197–198 (1994), 143–176. https://doi.org/10.1016/0024-3795(94)90486-3 doi: 10.1016/0024-3795(94)90486-3 |
[15] | A. Mohammadian, B. T. Rezaie, Graphs with four distinct Laplacian eigenvalues, J. Algebraic Combin., 34 (2011), 671–682. https://doi.org/10.1007/s10801-011-0287-3 doi: 10.1007/s10801-011-0287-3 |
[16] | P. Rowlinson, Z. Stanić, Signed graphs with three eigenvalues: Biregularity and beyond, Linear Algebra Appl., 621 (2021), 272–295. https://doi.org/10.1016/j.laa.2021.03.018 doi: 10.1016/j.laa.2021.03.018 |