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2410.19703

Pesin theory for transcendental maps and applications

Anna Jové

correcthigh confidence
Category
Not specified
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper’s Theorem A (and its stronger natural-extension version, Theorem 5.1) is clearly stated and proved under the hypotheses log|f'| ∈ L^1(ω_U), positive Lyapunov exponent χ_ωU(f)>0, and thin singular values in ∂U. The proof uses Rokhlin’s natural extension, ergodicity/recurrence of the boundary map, a summable control of harmonic measure near the singular set (Lemma 3.10), Borel–Cantelli, and Koebe distortion, yielding well-defined inverse branches on a uniform disk and exponential shrinking, and guaranteeing visits to any positive-measure set along a subsequence . The candidate solution mirrors this program in spirit (inner-function model, natural extension, summable windows, Borel–Cantelli, Koebe), but it crucially asserts the identity ∫∂D log|g'| dλ = ∫∂U log|f'| dω_U and treats their common value as a Lyapunov exponent for g. The paper explicitly lists this equality (χ_λ(g) = χ_ωU(f)) as an open question in the transcendental setting, even noting that proving it would simplify the positivity assumption for χ_ωU(f) . While the rest of the model’s outline could be salvaged without that claim (working entirely with f on ∂U, as the paper does), as written it depends on a step the paper identifies as open. Hence: paper correct; model, as stated, incorrect on a key point.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper establishes Pesin-theory-type statements for boundaries of transcendental Fatou components under natural conditions. The methodology—natural extension, summable avoidance of singular sets, and Koebe distortion—is carefully implemented and yields robust conclusions (inverse-branch existence, shrinking, and density applications). Only minor clarifications and examples are suggested to enhance readability.