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2202.12372

The Parabolic and Near-Parabolic Renormalization for a Class of Polynomial Maps and Its Applications

Xu Zhang

correctmedium confidence
Category
math.DS
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:56 AM

Audit review

The candidate solution is a faithful specialization of Zhang’s result to the one-parameter family P_α(z)=e^{2πiα}z(1+z)^m, relying on exactly the parabolic/near‑parabolic renormalization scheme and the Buff–Chéritat–style area argument developed in the paper. The paper proves existence of non‑renormalizable polynomials with a Cremer fixed point and positive‑area Julia set for degrees ≥22 (Theorem 1.1), and Section 3 works directly with P_α. Minor clarifications: the renormalization framework is proved for m≥22 (so deg P_α=m+1≥23), and the near‑parabolic renormalization requires small complex α with angle bounds and certain high‑type conditions. These do not contradict the candidate’s existence claim for m≥22 but should be noted.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper develops a high-degree parabolic/near-parabolic renormalization class tailored to P(z)=z(1+z)\^m and leverages it to obtain non-renormalizable polynomials with positive-area Julia sets and Cremer fixed points for degree ≥22. The approach extends the Buff–Chéritat program beyond the quadratic setting. While technically solid, a few clarifications on the degree threshold and precise parameter conditions would improve readability and avoid confusion about the m vs. degree boundary.