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2411.18418

Horocyclic Trajectories in Hyperbolic Solenoidal Surfaces of Finite Type

Fernando Alcalde Cuesta, Álvaro Carballido Costas, Matilde Martínez, Alberto Verjovsky

correctmedium confidence
Category
Not specified
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper proves the dichotomy rigorously (Theorem 2): for Y = Γ \ (PSL(2,R) × G) arising from a hyperbolic McCord solenoid, every horocycle orbit either projects to a periodic base orbit or is dense in Y, via a three-step argument using unique ergodicity of dense subgroup actions on G, Furstenberg’s equivalence, and Moore’s ergodicity to obtain a dense hR-orbit and then propagate density across fibers and to any point whose projection is nonperiodic . The model’s topological proof attempts to “synchronize” base density with fiber density by prescribing elements δm ∈ Γ while choosing return times tm, but its key step—asserting that pr(u0 n_{tm}) ∈ pr(δmB) implies u0 n_{tm} ∈ δmB—is false in general; one only gets u0 n_{tm} ∈ γ δm B for some γ ∈ Γ. Without an additional synchronization or measure-equidistribution input, the model’s argument does not conclude density. The McCord/principal bundle setup and the dense image ρ(Γ) ⊂ G are correctly stated (and used in the paper) , but the model omits the ergodic step that the paper leverages to bridge this gap.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper extends a classical dichotomy to a solenoidal setting with a clear, rigorous proof and adds a useful analysis of minimal sets and geodesic-time limits. The contributions are sound and well motivated; a few clarifications would enhance accessibility to readers less familiar with the McCord framework and standard ergodic results.