The fixed point of the parabolic renormalization operator

Abstract

We study parabolic renormalization of analytic germs with a simple parabolic point at the origin. We describe a class of maps $\mathbf P$ which admit a maximal analytic extension to a Jordan domain, and whose covering properties have an explicit topological model. We demonstrate that $\mathbf P$ is invariant under parabolic renormalization, and that Inou-Shishikura fixed point $f_*$ lies in $\mathbf P$. We conjecture that successive parabolic renormalizations of every map in $\mathbf P$ converge to $f_*$ at a geometric rate. We further present a numerical method for computing the Taylor's expansion of $f_*$ with a high accuracy. Our approach also allows us to compute the images of the maximal domain of analyticity of $f_*$. Finally, we obtain numerical estimates on the spectral radius of the differential of the parabolic renormalization operator at $f_*$.