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G-2007-72

Bounds on the Index of the Signless Laplacian of a Graph

, , , and

BibTeX reference

Let be a simple, undirected graph of order and size with vertex set , edge set , adjacency matrix and vertex degrees . The average degree of the neighbor of vertex is . Let be the diagonal matrix of degrees of . Then is the Laplacian matrix of and the signless Laplacian matrix of . Let denote the index of and the index of . We survey upper bounds on and given in terms of the and , as well as of the numbers of common neighbors of pairs of vertices. It is well known that . We show that many but not all upper bounds on are still valid for .

, 14 pages

This cahier was revised in April 2008

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Bounds on the index of the signless Laplacian of a graph
, , , and
Discrete Applied Mathematics, 158(4), 355–360, 2010 BibTeX reference