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2103.02254

The Exact Value of Hausdorff Dimension of Escaping Sets of Class B Meromorphic Functions

Volker Mayer, Mariusz Urbański

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

Audit review

The paper proves HD(I(f)) = lim_{R→∞} HD(IR(f)) = δ for f ∈ B with no asymptotic value at ∞ and uniformly bounded pole orders (Theorem 1.3), via an upper bound from natural covers and a lower bound using a carefully constructed non‑autonomous IFS after a desingularizing change of variables u(ξ)=ξ^{-M} and triple compositions Φ_{l,j} ensuring bounded distortion and uniform contraction; see the statement of Theorem 1.3 and its proof outline, Proposition 3.4, Lemma 5.3–5.4, and Theorem 4.1 summarized in the paper . By contrast, the candidate asserts (i) HD(IR(f)) = δ for all sufficiently large R and (ii) HD(ER(f)) = HD(X_R) by a purported uniform bi‑Lipschitz transfer; both are unsupported. In fact, the paper notes that often HD(IR(f)) > δ for every R > 0, even though lim_{R→∞} HD(IR(f)) = δ (Remark 7.5), contradicting the model’s claim of equality for large R .

Referee report (LaTeX)

\textbf{Recommendation:} no revision

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper establishes an exact, computable formula for the Hausdorff dimension of the escaping set for a broad and important class of meromorphic functions, using a robust non-autonomous IFS construction that overcomes limitations of earlier techniques. The arguments are carefully structured and justified, and the methodology should be influential for related dimension problems in transcendental dynamics.