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2201.05661

On Non-Contractible Periodic Orbits and Bounded Deviations

Xiao-Chuan Liu, Fábio Armando Tal

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

Audit review

The paper proves the stated dichotomy rigorously: it reduces the rotation-set geometry using standard lemmas (Misiurewicz–Ziemian; Franks) and then combines a new bounded-deviation theorem for line-segment rotation sets (its Theorem 1.3) with prior bounded-deviation results to deduce a strong irrational dynamical direction; in the Hamiltonian case, a prior result of Le Calvez–Tal gives uniform boundedness under the inessential fixed-set hypothesis. By contrast, the candidate solution is logically incomplete: in the segment case it invokes the very Liu–Tal classification it is supposed to justify (circular), and in the {0} case it misattributes and overuses the “either bounded or non-contractible periodic orbits” dichotomy to conclude boundedness from the absence of non-contractible periodic orbits, instead of correctly appealing to the Hamiltonian boundedness lemma. Overall, the paper’s argument is correct and complete for the stated result, whereas the model’s proof outline contains circular reasoning and mis-citations.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The manuscript offers a clean classification for area-preserving torus homeomorphisms under natural hypotheses, grounded in a new bounded-deviation theorem and classical rotation-set facts. The overall structure is clear and the arguments appear sound. Minor clarifications would enhance readability, particularly regarding the scope of non-wandering assertions and the exclusivity in the stated dichotomies.