Abstract
Let q(G) denote the signless Laplacian spectral radius of a graph G. In this paper, we first give an upper bound on q(G) of a connected graph G with fixed size \(m\ge 3k(k \in {\mathbb {Z}}^{+})\) and maximum degree \(\Delta \le m-k\). For two connected graphs \(G_1\) and \(G_2\) with size \(m\ge 4\), employing this upper bound, we prove that \(q(G_1)>q(G_2)\) if \(\Delta (G_1)>\Delta (G_2)\) and \(\Delta (G_1)\ge \frac{2m}{3}+1\). As an application, we determine the first \(\lfloor d/2\rfloor \) graphs with the largest signless Laplacian spectral radius among all graphs with fixed size and diameter.
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References
Bollobás, B., Lee, J., Letzter, S.: Eigenvalues of subgraphs of the cube. Eur. J. Combin. 70, 125–148 (2018)
Brualdi, R.A., Hoffman, A.J.: On the spectral radius of \((0,1)-\)matrices. Linear Algebra Appl. 65, 133–146 (1985)
Cvetković, D.: Some possible directions in further investigations of graph spectra, Algebra Methods in Graph Theory, pp. 47–67. North-Holland, Amsterdam (1981)
Cvetković, D., Rowlinson, P., Simić, S.: Eigenvalue bounds for the signless Laplacian. Publ. Inst. Math. (Beograd) 81(95), 11–27 (2007)
Cvetković, D., Rowlinson, P., Simić, S.: Signless Laplacian of finite graphs. Linear Algebra Appl. 423, 155–171 (2007)
Cvetković, D., Simić, S.: Towards a spectral theory of graphs based on the signless Laplacian. I, Publ. Inst. Math. (Beograd). 85(99), 19–33 (2009)
Das, K.C.: The Laplacian spectrum of a graph. Comput. Appl. Math. 48, 715–724 (2004)
Edwards, C., Elphick, C.: Lower bounds for the clique and the chromatic number of a graph. Discret. Appl. Math. 5, 51–64 (1983)
Feng, L.H., Yu, G.H.: On three conjectures involving the signless Laplacian spectral radius of graphs. Publ. Inst. Math. (Beograd) 85(99), 35–38 (2009)
Guo, J.M.: On the Laplacian spectral radius of trees with fixed diameter. Linear Algebra Appl. 419, 618–629 (2006)
Hong, Y., Zhang, X.D.: Sharp upper and lower bounds for largest eigenvalue of the Laplacian matrices of trees. Discret. Math. 296, 187–197 (2005)
Huang, P., Li, J.X., Shiu, W.C.: Maximizing the signless Laplacian spectral radius of \(k-\)connected graphs with given diameter. Linear Algebra Appl. 617, 78–99 (2021)
Li, J.S., Zhang, X.D.: On the Laplacian eigenvalues of a graph. Linear Algebra Appl. 285, 305–307 (1998)
Liu, M., Liu, B.: Extremal Theory of Graph Spectrum. University of Kragujevac and Faculty of Science Kragujevac, Kragujevac (2018)
Liu, M., Liu, B., Cheng, B.: Ordering (signless) Laplacian spectral radii with maximum degrees of graphs. Discret. Math. 338, 159–163 (2015)
Lou, Z.Z., Guo, J.M., Wang, Z.W.: Maxima of \(L-\)index and \(Q-\)index: graphs with given size and diameter. Disctere Math. 344, 112533 (2021)
Merris, R.: A note on Laplacian graph eigenvalues. Linear Algebra Appl. 285, 33–35 (1998)
Nikiforov, V.: More spectral bounds on the clique and independence. J. Combin. Theory Ser. B 99, 819–826 (2009)
Oliveira, C.S., de Limab, L.S., de Abreu, N.M.M., Hansen, P.: Bounds on the index of the signless Laplacian of a graph. Discret. Appl. Math. 158, 355–360 (2010)
Rowlinson, P.: On the maximal index of graphs with a prescribed number of edges. Linear Algebra Appl. 110, 43–53 (1988)
Stanić, Z.: Inequalities for Graph Eigenvalues, London Mathematical Society Lecture Note Series, 423. Cambridge University Press, Cambridge (2015)
Stanley, R.P.: A bound on the spectral radius of graphs with edges. Linear Algebra Appl. 87, 267–269 (1987)
Stevanović, D.: Spectral Radius of Graphs. Academic Press, New York (2015)
Tait, M., Tobin, J.: Three conjectures in extremal spectral graph theory. J. Combin. Theory Ser. B 126, 137–161 (2017)
Wilf, H.S.: The eigenvalue of a graph and its chromatic number. J. London Math. Soc. 42, 330–332 (1967)
Zhai, M.Q., Wang, B., Fang, L.F.: The spectral Turán problem about graphs with no \(6\)-cycle. Linear Algebra Appl. 590, 22–31 (2020)
Zhai, M.Q., Xue, J., Lou, Z.Z.: The signless Laplacian spectral radius of graphs with a prescribed number of edges. Linear Algebra Appl. 603, 154–165 (2020)
Zhai, M.Q., Xue, J., Liu, R.: An extremal problem on \(Q\)-spectral radii of graphs with given size and matching number. Linear Multilinear Algebra (2021). https://doi.org/10.1080/03081087.2021.1915231
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The authors are grateful to the anonymous referees for valuable suggestions and corrections which result in an improvement of the original manuscript.
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Communicated by Sandi Klavžar.
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Supported by the National Natural Science Foundation of China (Nos. 12071411, 12171222)
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Zhang, R., Guo, SG. Ordering Graphs with Given Size by Their Signless Laplacian Spectral Radii. Bull. Malays. Math. Sci. Soc. 45, 2165–2174 (2022). https://doi.org/10.1007/s40840-022-01312-1
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DOI: https://doi.org/10.1007/s40840-022-01312-1