Equidistribution of repelling fixed points for iterates of rational functions

Prove that for every rational function R over an algebraically closed, complete non-archimedean field, with degree at least two, the degree-weighted measures supported on the repelling fixed points of the iterates R^n, normalized by (deg R^n)^{-1}, converge weakly to the equilibrium measure of R as n tends to infinity.

Background

The paper identifies the general equidistribution of repelling fixed points as a question posed by Favre and Rivera-Letelier. Unlike preimages and all periodic points, repelling fixed points in the Berkovich projective line do not have an immediately uniform counting formula, because their number and local-degree distribution can vary with the rational function.

The paper proves the conjectured convergence for polynomials and for rational functions with positive Lyapunov exponent, and obtains a conditional result for rational functions with connected Julia set. The general statement therefore remains unresolved in the paper.

References

Their Question 1 then asks whether equidistribution holds for repelling periodic points. In , the same authors rephrase this question in a more precise way in their Conjecture 1, which we state here below. Let $R\in K(z)$ be a rational function with $\deg R \geq 2$, denote by $(Rn)$ the set of repelling fixed points of $Rn$, and let $\sigma_R = \sum_{\zeta \in (R)} (\deg_R \zeta)\times\delta_\zeta$. Then $(\deg Rn){-1}\sigma_{Rn} \xrightarrow[n\to\infty]{} \nu_R$ weakly.

Counting non-attracting subtrees and the equidistribution of repelling points  (2608.14200 - Bottiglione, 14 Aug 2026) in Introduction; Conjecture 1 of Favre and Rivera-Letelier, labeled Question 1′ in the paper