2106.11859
Functional analysis approach to the Collatz conjecture
Mikhail Neklyudov
wronghigh confidence
- Category
- math.DS
- Journal tier
- Specialist/Solid
- Processed
- Sep 28, 2025, 12:56 AM
- arXiv Links
- Abstract ↗PDF ↗
Audit review
The paper states Theorem 2.2 for the Hardy space H^2(B0(1))/X, but its hypercyclicity proof computes ||S^n z^k||^2 = π/(2^n k + 1) → 0, which is the Bergman norm decay, not Hardy (where ||z^m||_{H^2} = 1), so the key step S^n→0 fails on Hardy and the proof is invalid as written . The operator and its action T(z^n)=z^{T(n)} are correctly defined, and the right inverse Sg(z)=g(z^2) does satisfy T∘S=Id . However, the divergent-orbit case is asserted “similar” without details and, as stated, cannot use the same dense set argument in H^2. The candidate solution fixes the space to the unweighted Bergman space A^2(D) (where ||z^m||^2=1/(m+1)), for which S^n→0 on polynomials and the Hypercyclicity Criterion applies; that argument is correct and fully consistent with the paper’s intended coefficient computations.
Referee report (LaTeX)
\textbf{Recommendation:} major revisions
\textbf{Journal Tier:} specialist/solid
\textbf{Justification:}
The paper presents an appealing operator-theoretic framing of Collatz dynamics and several illustrative results. However, the principal hypercyclicity theorem is stated on the Hardy space but proved using Bergman-space norms, so the argument is incorrect in the stated setting. With a corrected statement (to Bergman) and a complete treatment or retraction of the divergent-orbit case, the contribution would be solid.