Bounds for Incidence Energy of Some Graphs

LetG be a finite, simple, and undirected graphwith n vertices. Thematrix L(G) = D(G)−A(G) (resp., L+(G) = D(G)+A(G)) is called the Laplacianmatrix (resp., signless Laplacianmatrix [1–4]) of G, where A(G) is the adjacency matrix and D(G) is the diagonal matrix of the vertex degrees. (For details on Laplacian matrix, see [5, 6].) Since A(G), L(G) and L+(G) are all real symmetric matrices, their eigenvalues are real numbers. So, we can assume that λ 1 (G) ≥ λ 2 (G) ≥ ⋅ ⋅ ⋅ ≥