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2011.15043

Dynamical Systems Around the Rauzy Gasket and Their Ergodic Properties

Ivan Dynnikov, Pascal Hubert, Alexandra Skripchenko

correctmedium confidence
Category
math.DS
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:55 AM

Audit review

The paper’s Theorem 1.1 proves that the four constructions—(a) the mapping torus (Σ_AR_λ,F_AR_λ), (b) the RP^2 branched-cover model (Σ_λ,F_λ), (c) the PL model in T^3 (Σ_PL,F^PL_λ), and (d) the double suspension Σ(S_λ,θ_λ)—all yield equivalent measured foliations for λ∈Δ\∂Δ, by exhibiting closed transversals whose first-return map is TAR_λ and invoking direct identifications (Propositions 5.1, 6.1, 8.1) . The candidate solution follows the same blueprint: a reconstruction-from-return-data lemma and explicit transversals realizing the same TAR_λ (with the six lengths λ_i/2 and the rotation by 1/2) , then concluding equivalence. Minor differences: the paper states exact isomorphisms for (a)↔(b) and (a)↔(c) (no rescaling), and an explicit factor 2 for (a)↔(d) , whereas the model allows unspecified global scalings and suggests a covering-degree scaling in (b), which is unnecessary. Overall, both arguments are materially the same and correct; the model’s lemma is the standard cut-and-glue/zippered-rectangle reconstruction implicitly used in the paper.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper unifies multiple constructions surrounding the Rauzy gasket by proving they produce the same family of genus-3 measured foliations. The strategy—identify a common Poincaré return IET and reconstruct—is clean and persuasive, and the normalization (factor 2) in the double-suspension case is handled explicitly. Given the breadth across communities (IETs, Novikov’s problem, systems of isometries), the work will be valuable to specialists. Minor additions (an explicit reconstruction lemma and a brief normalization summary) would enhance readability but are not essential to the main results.