Bounds of distance Estrada index of graphs

Yilun Shang

Let ${\lambda }_1,{\lambda }_2,\cdots ,{\lambda }_n$ be the eigenvalues of the distance matrix of a connected graph $G$. The distance Estrada index of $G$ is defined as $DEE(G)={\sum }_{i=1}^n{e}^{{\lambda }_i}$. In this n…