The Laplacian-energy like of graphs

Assume that μ 1 , μ 2 , … , μ n are eigenvalues of the Laplacian matrix of a graph G . The Laplacian-energy like of G , is defined as follows: LEL ( G ) = ∑ i = 1 n μ i . In this note, we give upper bounds for L E L ( G ) in terms of connectivity or chromatic number and characterize the corresponding extremal graphs.