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2109.04836

Superdensity and Super-Micro-Uniformity in Non-Integrable Flat Systems

J. Beck, W.W.L. Chen

correctmedium confidence
Category
math.DS
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper proves super-micro-uniformity for half-infinite geodesics on polysquare (square-tiled) surfaces with badly approximable slope by a careful density-transport/iteration argument leveraging a superdensity input, culminating in the bound |V_n(I) − n|I|/b| < ε n|I|/b for all subintervals |I| > C_ε/n, with C_ε independent of n. This is documented explicitly (statement of Theorem 1 and its proof, including the Case A/Case B dichotomy and the final estimate) . By contrast, the candidate solution asserts a much stronger O(1) absolute discrepancy via a cohomological-equation approach for Roth-type IETs applied to step functions. That would imply every interval is a bounded remainder set even for circle rotations (the b=1 case), which is known to be false in general (bounded remainder intervals are exceptional). The candidate’s use of MMY-type results is inapplicable to discontinuous step observables without resolving cohomological obstructions, and its reduction from “badly approximable slope” to the Roth/ bounded-type IET conditions is not justified.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The work gives an optimal micro-uniformity consequence of superdensity for non-integrable flat systems. The argument, while technical, is carefully structured and quantitatively explicit. Minor expository enhancements (self-contained statement of the superdensity input, a constants table, and a schematic of the iteration) would improve readability but do not affect correctness.