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2107.01708

Rescaled-Expansive Flows: Unstable Sets and Topological Entropy

Alexander Arbieto, Alfonso Artigue, Elias Rego

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

Audit review

The paper’s Theorem D (non-periodic attractor without singularities in an R-expansive flow implies positive entropy) is proved by showing such an attractor has no R-stable/unstable points, then invoking Theorems B and C to obtain h(φ) > 0; the steps are explicit in the text and consistent with earlier results. By contrast, the model’s proof hinges on claiming the time-one map is cw-expansive on Γ; that claim is false in general because arbitrarily small orbit arcs remain uniformly small under all iterates, contradicting cw-expansiveness for homeomorphisms. Hence the model’s reasoning is flawed even though it reaches the correct conclusion.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The work develops a rescaled local stable/unstable-set theory tailored to R-expansive flows and uses it to prove a compelling entropy result for non-periodic attractors without singularities. The argument is internally consistent and builds cleanly on the introduced tools. Some exposition could be clarified (especially the bridge from R-expansiveness in the non-singular regime to the flow-level cw-expansive entropy criterion), but the results appear correct and of specialized interest.