2504.18192
Recent progress on pointwise normality of self-similar measures
Amir Algom
correcthigh confidence
- Category
- Not specified
- Journal tier
- Strong Field
- Processed
- Sep 28, 2025, 12:56 AM
- arXiv Links
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Audit review
The paper proves Theorem 1.2: any non-atomic self-similar Rajchman measure is pointwise absolutely normal, via a conditional-measure/partition method (Theorem 2.1) and a Fourier-mode criterion (Lemma 3.1), then shows the Rajchman property forces those Fourier modes to vanish uniformly after suitable scaling; see Theorem 1.2, Lemma 3.1, and the conclusion of Section 3 (including the use of the identity \hat T_b^n \circ c = c \circ T_b^n for integer b) . The candidate solution instead attempts a direct van der Corput/L^2 approach and then (incorrectly) applies Chebyshev plus Borel–Cantelli to a tail sup over N. That step is invalid: one cannot bound μ({sup_{N≥N_j}|S_N|>a}) by sup_{N≥N_j} E|S_N|^2/a^2, and a union bound would require summability over N, which fails for the obtained O(1/N) L^2 bounds. Moreover, the candidate’s method, if correct, would imply the (false) general statement that every Rajchman measure is pointwise absolutely normal, contradicting Lyons’ negative answer to the Kahane–Salem question cited in the paper .
Referee report (LaTeX)
\textbf{Recommendation:} minor revisions \textbf{Journal Tier:} strong field \textbf{Justification:} The paper consolidates and clarifies a significant recent advance: that the Rajchman property suffices for pointwise absolute normality within the class of self-similar measures. The proof is self-contained and technically clean, hinging on a well-presented conditional-measure method and a Fourier-mode criterion. The contribution is timely, situating the result relative to classical approaches and highlighting sharp boundaries (Lyons’ counterexamples). Minor clarifications would further improve readability.