Comparison between Kirchhoff index and the Laplacian-energy-like invariant

Autor: Kexiang Xu, Ivan Gutman, Kinkar Ch. Das
Rok vydání: 2012
Předmět:
Zdroj: Linear Algebra and its Applications. 436(9):3661-3671
ISSN: 0024-3795
DOI: 10.1016/j.laa.2012.01.002
Popis: Let G be a connected graph of order n with Laplacian eigenvalues μ 1 ⩾ μ 2 ⩾ ⋯ ⩾ μ n - 1 > μ n = 0 . The Kirchhoff index and the Laplacian-energy-like invariant of G are defined as Kf = n ∑ k = 1 n - 1 1 / μ k and LEL = ∑ k = 1 n - 1 μ k , respectively. We compare Kf and LEL and establish two sufficient conditions under which LEL Kf . The connected graphs of order n with nine greatest Kirchhoff indices are determined; for these LEL > Kf holds.
Databáze: OpenAIRE