Let $X$ be an orientable hyperbolic surface of genus $g\geq 2$ with a marked point $o$, and let $\Gamma$ be an orientable hyperbolic surface group isomorphic to $\pi_{ 1}(X,o)$. Consider the space $\text{ Hom}(\Gamma,S_{ n})$ which corresponds to $n$-sheeted covers of $X$ with labeled fiber. Given $\gamma\in\Gamma$ and a uniformly random $\phi\in\text{ Hom}(\Gamma,S_{ n})$, what is the expected number of fixed points of $\phi(\gamma)$? Formally, let $F_{ n}(\gamma)$ denote the number of fixed points of $\phi(\gamma)$ for a uniformly random $\phi\in\text{ Hom}(\Gamma,S_{ n})$. We think of $F_{ n}(\gamma)$ as a random variable on the space $\text{ Hom}(\Gamma,S_{ n})$. We show that an arbitrary fixed number of products of the variables $F_{ n}(\gamma)$ are asymptotically independent as $n\to\infty$ when there are no obvious obstructions. We also determine the limiting distribution of such products. Additionally, we examine short cycle statistics in random permutations of the form $\phi(\gamma)$ for a uniformly random $\phi\in\text{ Hom}(\Gamma,S_{ n})$. We show a similar asymptotic independence result and determine the limiting distribution.
Categories: math.GR math.CO math.PR