Fig. 5

Approximating the sum S. Numerical evidence showing that the mean of $S=\frac{1}{{(n-1)}^2}{\sum }_{i=2}^n{\sum }_{j=2}^n\left(\frac{-1}{{\lambda }_i+{\lambda }_j}\right)$ is well approximated by $1/(2pn)$, for the Erdös–Rényi ensemble with $p\ge 0.3$. For a given value of p, the colored asterisks show the sample mean of S as a function of n over 10 realizations (with error bars showing the standard deviation) and the black curve is $1/(2pn)$