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2404.13642

CAN POINTS OF BOUNDED ORBITS SURROUND POINTS OF UNBOUNDED ORBITS ?

JIEHUA MAI, ENHUI SHI, KESONG YAN, FANPING ZENG

correcthigh confidence
Category
Not specified
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper proves that for any disk E ⊂ R^2 there is a plane homeomorphism h with bounded orbits on ∂E and doubly divergent orbits on Int(E), via a construction on J^2 using normally rising homeomorphisms (Theorems 1.2 and 3.5) and a conjugacy pipeline employing a semi-conjugacy ξ, a coordinate blow-up ψ, and the Schönflies theorem ζ . The candidate solution gives a different, explicit construction: h = u ∘ T where T is a translation and u is a compactly supported shear inverse that fixes ∂E pointwise and leaves all interior orbits asymptotically like T in both time directions, hence doubly divergent. The argument is sound; minor technical points (e.g., support of u vs. j) are easily patched. Thus both the paper and the model are correct, with substantially different proofs.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The manuscript demonstrates, with a carefully crafted construction on J\^2 and subsequent conjugacies, that a disk’s boundary can consist entirely of bounded orbits while its interior points all have doubly divergent orbits. The approach is technically sound and leverages a novel class of ‘normally rising’ homeomorphisms to encode prescribed limit-set behavior. Some steps—particularly the definition and properties of the semi-conjugacy ξ leading to the homeomorphism g—would benefit from fuller exposition and an accompanying figure, but these are presentational refinements rather than correctness issues.