PreprintarXiv licencearXiv
Multicritical pseudo-Siegel bounds and the optimality of the Brjuno condition for all neutral polynomials
Abstract
We establish uniform multicritical pseudo-Siegel bounds for polynomials of Zakeri type, where all free critical points are on the boundary of an invariant Siegel disk of bounded type. This generalizes the unicritical result~\cite{DL:wZ}. As an application, we show the optimality of the Brjuno condition under the Zakeri restriction: as the rotation number becomes non-Brjuno, the Siegel disk evolves into the Cremer Hedgehog. Combined with~\cite{BCR26}, this implies the optimality of the Brjuno condition for all neutral polynomials, resolving a conjecture by Douady from the 1980s.
Related
- Upper Bounds and Fekete–Szegö Problem for Bi-Univalent Functions Involving Bazilevič and λ-Pseudo Functions Related to Lucas-Balancing Polynomials
- Power sums of critical points of gap polynomials for symmetric and pseudo-symmetric numerical semigroups
- Ising-machine-like Driving Condition Restrictions in SSBM and Additional Pseudo-annealing- Driving Method for SSBM that Achieves Best Cut Value Search -
- Subsampled Pseudo-posteriors for Scalable Bayesian Moment-condition Inference
- Lebesgue measure of the postcritical set of neutral quadratic polynomials
BibTeX
@misc{dudko2026multicritical,
title = {{Multicritical pseudo-Siegel bounds and the optimality of the Brjuno condition for all neutral polynomials}},
author = {Dzmitry Dudko and Yusheng Luo and Runze Zhang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.37468},
eprint = {2610.37468},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.37468},
}
RIS
TY - UNPB
TI - Multicritical pseudo-Siegel bounds and the optimality of the Brjuno condition for all neutral polynomials
AU - Dzmitry Dudko
AU - Yusheng Luo
AU - Runze Zhang
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.37468
UR - https://arxiv.org/abs/2610.37468
AB - We establish uniform multicritical pseudo-Siegel bounds for polynomials of Zakeri type, where all free critical points are on the boundary of an invariant Siegel disk of bounded type. This generalizes the unicritical result~\cite{DL:wZ}. As an application, we show the optimality of the Brjuno condition under the Zakeri restriction: as the rotation number becomes non-Brjuno, the Siegel disk evolves into the Cremer Hedgehog. Combined with~\cite{BCR26}, this implies the optimality of the Brjuno condition for all neutral polynomials, resolving a conjecture by Douady from the 1980s.
ER -