More inequalities for Laplacian indices by way of majorization

Abstract

The n-tuple of Laplacian characteristic values of a graph is majorized by the conjugate sequence of its degrees. Using that result we find a collection of general inequalities for a number of Laplacian indices expressed in terms of the conjugate degrees, and then with a maximality argument, we find tight general bounds expressed in terms of the size of the vertex set n and the average degree dG = 2|E|/n. We also find some particular tight bounds for some classes of graphs in terms of customary graph parameters.