Revisiting the Maximum Principal Ratio of Graphs

Abstract

Let $G$ be a connected graph, the principal ratio of $G$ is the ratio of the maximum and minimum entries of its Perron eigenvector. In 2007, Cioab\v a and Gregory conjectured that among all connected graphs on $n$ vertices, the kite graph attains the maximum principal ratio. In 2018, Tait and Tobin confirmed the conjecture for sufficientlty large $n$. In this article, we show the conjecture is true for all $n\geq 5000$.