Extremal spectral radius of nonregular graphs with a fixed odd maximum degree
For integers $n\ge3$ and $2\le\Delta\le n-1$, let $\lambda_1(n,\Delta)$ be the maximum adjacency spectral radius among all connected nonregular graphs of order $n$ and maximum degree $\Delta$. Liu conjectured that for each fixed integer $\Delta\ge3$, \[ \lim_{n\to\infty}n^2\bigl(\Delta-\lambda_1(n,\Delta)\bigr)= \begin...