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2112.07346

A Continuous Family of Non-Monotonic Toral Mixing Maps

J. Myers Hill, R. Sturman, M. C. T. Wilson

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

Audit review

The uploaded paper proves that the map H = G∘F (with F(x,y) = (x + f(y), y), f(y) = y/(1−η) for y ≤ 1−η and f(y) = (1−y)/η for y ≥ 1−η; G(x,y) = (x, y + x)) has the Bernoulli property on two explicit parameter windows: 0 < η < η1 and η2 ≤ η < η3, with η1 ≈ 0.324, η2 ≈ 0.415, η3 ≈ 0.491. This is stated as Theorem 1 and established by verifying the Katok–Strelcyn conditions and the Repeated Manifold Intersection Property (MR) via Propositions 1–3 (Cat-map side) and 4–6 (CG-map side) . The candidate solution asserts that the status was likely open as of the cutoff and that RMIP had not been proved for this exact H in those ranges, but the paper explicitly constructs invariant expanding cone fields, growth schemes for local (un)stable segments, and geometric quadrilaterals ensuring that v-segments and h-segments map to themselves, thereby proving (MR) and hence Bernoulli on the stated windows . Therefore, the model's status assessment is incorrect.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The manuscript rigorously establishes the Bernoulli property for a non-monotonic toral linked-twist map over two explicit parameter windows by implementing the Katok–Strelcyn framework with precise geometric constructions. The contribution advances rigorous mixing theory past uniformly hyperbolic models and bridges notable examples (Cat and Cerbelli–Giona maps). While some threshold computations are presented numerically, the overall argument is carefully structured and technically sound.