On graphs having minimal fourth adjacency coefficient

Shi Cai Gong, Shi Wei Sun

Let $G$ be a graph with order $n$ and adjacency matrix $\mathbf{A}(G)$. The adjacency polynomial of $G$ is defined as $ϕ(G;λ) =det(λ\mathbf{I}-\mathbf{A}(G))=\sum_{i=0}^n\mathbf{a_…