2101.11120
RIGIDITY PROPERTIES FOR COMMUTING AUTOMORPHISMS ON TORI AND SOLENOIDS
Manfred Einsiedler, Elon Lindenstrauss
correctmedium confidence
- Category
- Not specified
- Journal tier
- Top Field-Leading
- Processed
- Sep 28, 2025, 12:55 AM
- arXiv Links
- Abstract ↗PDF ↗
Audit review
The uploaded paper states and proves Theorem 1.3 exactly as the four properties summarized in the SOLVER_QUESTION: after passing to a finite-index subgroup Λ, one gets a finite ergodic decomposition µ = (1/J)∑µj, closed subgroups Gj with µj translation-invariant, Zd permutes the pairs (µj, Gj), and the induced measures on X/Gj have zero entropy for all n ∈ Λ. See the theorem statement and its reduction to the adelic Theorem 4.1 (and the finite-index/ergodic-decomposition step) in Section 4.3 of the paper , with background definitions in the Introduction . By contrast, the candidate solution’s Step 4 invokes a global “positive-entropy rigidity” black box for general algebraic Zd-actions on solenoids to force translational symmetry on a factor; but that assertion is essentially the main new content established by this paper (via the adelic reduction and the entropy-identity machinery), not an available lemma under the model’s stated assumptions. The candidate also omits the necessary condition d ≥ 2 and does not handle the adelic normalization/finite-index choices that are crucial in the paper’s proof. Hence the paper gives a correct, complete proof, while the model’s outline is circular/incomplete.
Referee report (LaTeX)
\textbf{Recommendation:} minor revisions
\textbf{Journal Tier:} top field-leading
\textbf{Justification:}
This paper establishes a comprehensive positive-entropy measure rigidity theorem for commuting algebraic Zd-actions on tori and solenoids, settling the general case beyond earlier partial or conditional results. The adelic reduction and entropy-identity methods are technically sophisticated and broadly applicable, and the applications to joinings and measurable factors are compelling. Exposition is strong; a few minor additions would further aid readers navigating the adelic setup and entropy machinery.