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
- arXiv Links
- Abstract ↗PDF ↗
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.