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2011.14278

Nonsingular Transformations That Are Ergodic with Isometric Coefficients and Not Weakly Doubly Ergodic

James Leng, Cesar E. Silva

correctmedium confidence
Category
Not specified
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:55 AM

Audit review

The paper establishes all three claims for the nonsingular HK(+1, λ) system: type III_λ (Theorem 4.1), failure of WDE (Theorem 4.2), and EIC (Theorem 4.3), with coherent proofs grounded in the rank‑one construction and a dense‑orbit lemma for isometric factors . The candidate’s ratio‑set and non‑WDE arguments are essentially correct (though the “unique representation” of times needs a stronger growth condition than stated), but the EIC part omits the crucial dense‑orbit hypothesis and quantitative overlap estimate used in the paper; the asserted “pigeonhole along a long chain” does not by itself yield closeness in the isometric factor. Thus the paper is correct, while the model’s EIC proof is flawed/incomplete.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The work cleanly separates EIC from WDE in both infinite measure-preserving and nonsingular settings, including new type III\_λ examples. The arguments are solid and accessible to experts in rank-one constructions. Minor expository enhancements would further aid readability.