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2010.02046

A note on parabolic-like maps

Luna Lomonaco

correcthigh confidence
Category
math.DS
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:55 AM

Audit review

The paper’s note establishes that the C1 smoothness of the dividing arc in the definition of parabolic-like maps can be replaced by the condition that ∂Δ \ {z0} is a quasiarc, and it explains why the straightening theorem for degree 2 still goes through by ensuring the relevant boundary in the covering extension is a quasicircle, via a quasiarc ‘completion’ argument using [L1, Prop. 5.3(2)] (see the abstract, Definition 1.1, and Section 3.2.1 in the note ). The candidate solution reaches the same conclusions: Part (A) argues that quasiarc geometry suffices to define the external class and to carry out QC surgery; Part (B) gives a reduction to the classical C1 framework by taking a parabolic-like restriction and then applies Lomonaco’s straightening into Per1(1). The methodologies differ: the paper keeps the proof in the relaxed setting by completing the quasiarc to a quasicircle for the surgery step, whereas the candidate reduces to the original C1 setting by restriction. No substantive conflict is found; the candidate’s quasisymmetric boundary framework is a slightly weaker regularity statement than the paper’s real-analytic external map on S1, but it does not contradict the paper and suffices for surgery.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The note isolates and removes an unnecessary \$C\^1\$ hypothesis in the definition of parabolic-like maps, showing that a quasiarc condition on \$\partial\Delta\setminus\{z\_0\}\$ suffices for the degree-2 straightening theorem and for maintaining the standard properties of the theory. The argument is brief, correct, and leverages prior results effectively. Minor additions clarifying the quasiarc-to-quasicircle completion and boundary regularity would enhance accessibility.