Bounds for the Huckel energy of a graph

Ebrahim Ghorbani, Jack H. Koolen, Jae Young Yang

Let $G$ be a graph on $n$ vertices with $r:=\lfloor n/2\rfloor$ and let ${\lambda }_1\ge ...\ge {\lambda }_n$ be adjacency eigenvalues of $G$. Then the Hückel energy of $G$, HE($G$), is defi…