The Laplacian spectral radius of trees and maximum vertex degree

Trees with given maximum degree minimizing the spectral radius

The spectral radius of a graph is the largest eigenvalue of the adjacency matrix of the graph. Let T (n,∆, l) be the tree which minimizes the spectral radius of all trees of order n with exactly l vertices of maximum degree ∆. In this paper, T (n,∆, l) is determined for ∆ = 3, and for l ≤ 3 and n large enough. It is proven that for sufficiently large n, T (n, 3, l) is a caterpillar with (almost...

Ela Distance Spectral Radius of Trees with Fixed Maximum Degree∗

Abstract. Distance energy is a newly introduced molecular graph-based analog of the total π-electron energy, and it is defined as the sum of the absolute eigenvalues of the molecular distance matrix. For trees and unicyclic graphs, distance energy is equal to the doubled value of the distance spectral radius. In this paper, we introduce a general transformation that increases the distance spect...

Distance spectral radius of trees with fixed maximum degree

On the extremal total irregularity index of n-vertex trees with fixed maximum degree

In the extension of irregularity indices, Abdo et. al. [1] defined the total irregu-larity of a graph G = (V, E) as irrt(G) = 21 Pu,v∈V (G) du − dv, where du denotesthe vertex degree of a vertex u ∈ V (G). In this paper, we investigate the totalirregularity of trees with bounded maximal degree Δ and state integer linear pro-gramming problem which gives standard information about extremal trees a...

The p-Laplacian spectral radius of weighted trees with a degree sequence and a weight set

In this paper, some properties of the discrete p-Laplacian spectral radius of weighted trees have been investigated. These results are used to characterize all extremal weighted trees with the largest p-Laplacian spectral radius among all weighted trees with a given degree sequence and a positive weight set. Moreover, a majorization theorem with two tree degree sequences is presented.