Equidistribution speed of iterated preimages for rational maps on the Riemann sphere
Mai Hao, Zhuchao Ji
TL;DR
This work provides a near-optimal quantitative equidistribution speed for iterated preimages under rational maps on the Riemann sphere ${\mathbb P}^1$. It delivers a sharp $O(n d^{-n})$ rate for points not in super-attracting cycles in general, and strengthens to $O(d^{-n})$ for geometrically finite maps, including all hyperbolic maps, by combining potential-theoretic truncations with diameter estimates of inverse branches. The authors compare geometric, diameter-based methods with Nevanlinna-theoretic approaches and derive explicit constants; independent results by Okuyama support the $O(nd^{-n})$ rate. The results advance quantitative understanding of equidistribution towards the maximal entropy measure $\mu_f$ and have potential implications for the effective dynamics of rational maps on ${\mathbb P}^1$ and related moduli spaces.
Abstract
The exponential equidistribution speed of iterated preimages for holomorphic endomorphisms on $\mathbb{P}^k$ was established by Drasin-Okuyama for $k=1$, and by Dinh-Sibony for arbitrary $k$. In this paper, we obtain a near-optimal equidistribution speed with order $O(nd^{-n})$ in dimension one for points that are not super-attracting periodic. For geometrically finite rational maps (including all hyperbolic rational maps), we prove that the equidistribution speed order is $O(d^{-n})$ for points that are not super-attracting, attracting, or parabolic periodic.
