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2408.11256

AN ANALOGUE OF GREEN’S FUNCTIONS FOR QUASIREGULAR MAPS

Mark Broderius, Alastair N. Fletcher

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

Audit review

The paper proves existence of a nonnegative continuous function GK,θ,c with GK,θ,c∘H=2GK,θ,c, positive on the escaping set and zero on the bounded orbit set, by building a τ-semi-conjugacy via a Böttcher-type conjugacy near infinity and pulling back to all of I(H), then extending by 0 on BO(H) (Theorem 1.1; construction around Lemmas 3.5–3.9 and Theorem 2.5) . The candidate solution independently constructs G via the escape-rate limit G(z)=limn→∞2−n log+|Hn(z)|, justified using global growth bounds akin to Lemma 2.4 (|H(z)|≈|z|2 near infinity) to obtain uniform Cauchy convergence, the functional equation, and the correct zero/positivity sets . Both arrive at the same conclusion through different methods.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The manuscript rigorously constructs a Green-type escape function for degree-two planar quasiregular maps of the form Pc∘hK,θ and leverages it to study equipotentials and connectivity properties. The approach via a τ-semi-conjugacy and Böttcher-type conjugacy near infinity is clean and the pullback extension to all of I(H) is handled carefully. A few clarifications (explicit escape radii, a note on potential uniqueness of G, and a short comparison to the escape-rate construction) would improve accessibility, but do not affect correctness.