Remarks on the Degree Kirchhoff Index


M. Matejić, I. Milovanović, E. Milovanović




Let $G$ be a simple connected graph with $n$ vertices and $m$ edges, with normalized Laplacian eigenvalues $\rho_1\geq \rho_2\geq \cdots\geq \rho_{n-1}>\rho_n=0$. The degree Kirchhoff index $Kf^{\ast}(G)$ is defined as $Kf^{\ast}(G)=2m \sum_{i=1}^{n-1}\frac{1}{\rho_{i}}$. In this paper we obtain lower and upper bounds for $Kf^{\ast}(G)$.