On the Faria's inequality for the Laplacian and signless Laplacian spectra: A unified approach

Graphs determined by their (signless) Laplacian spectra

Let S(n, c) = K1∨(cK2∪(n−2c−1)K1), where n ≥ 2c+1 and c ≥ 0. In this paper, S(n, c) and its complement are shown to be determined by their Laplacian spectra, respectively. Moreover, we also prove that S(n, c) and its complement are determined by their signless Laplacian spectra, respectively.

THE SPECTRAL DETERMINATION OF THE MULTICONE GRAPHS Kw ▽ C WITH RESPECT TO THEIR SIGNLESS LAPLACIAN SPECTRA

The main aim of this study is to characterize new classes of multicone graphs which are determined by their signless Laplacian spectra. A multicone graph is defined to be the join of a clique and a regular graph. Let C and K w denote the Clebsch graph and a complete graph on w vertices, respectively. In this paper, we show that the multicone graphs K w ▽C are determined by their signless ...

Bibliography on the Signless Laplacian Eigenvalues

Nordhaus-Gaddum Type Inequalities for Laplacian and Signless Laplacian Eigenvalues

Let G be a graph with n vertices. We denote the largest signless Laplacian eigenvalue of G by q1(G) and Laplacian eigenvalues of G by μ1(G) > · · · > μn−1(G) > μn(G) = 0. It is a conjecture on Laplacian spread of graphs that μ1(G)−μn−1(G) 6 n − 1 or equivalently μ1(G) + μ1(G) 6 2n − 1. We prove the conjecture for bipartite graphs. Also we show that for any bipartite graph G, μ1(G)μ1(G) 6 n(n − ...

Eigenvalue Bounds for the Signless Laplacian

We extend our previous survey of properties of spectra of signless Laplacians of graphs. Some new bounds for eigenvalues are given, and the main result concerns the graphs whose largest eigenvalue is maximal among the graphs with fixed numbers of vertices and edges. The results are presented in the context of a number of computer-generated conjectures.