In this work, we define the Laplacian and Normalized Laplacian energies of vertices in a graph, we derive some of its properties and relate them to combinatorial, spectral and geometric quantities of the graph.
IntroductionNowadays, there are many notions of graph energies defined in the literature (see [12] for a review of them). In the present work we will focus our interest in the Laplacian ([13]) and normalized Laplacian ([6]) energies.We denote a graph by G = (V, E), with n vertices and m edges,is the vertex set, and E is the set of edges. The degree of a vertex v i is the number of vertices to which it is connected, and is denoted by d i . If there is an edge between two vertices v, w ∈ V we write v ∼ w. We will assume that G is simple and connected.The M−energy of a graph G was introduced in [6], where M is a matrix associated to G. The M-energy is defined by