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2006.10617

A BRANCHED COVERING OF DEGREE 2 OF THE SPHERE WITH A COMPLETELY INVARIANT INDECOMPOSABLE CONTINUUM.

J. Iglesias, A. Portela, A. Rovella, J. Xavier

correcthigh confidence
Category
Not specified
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:55 AM

Audit review

The paper explicitly constructs a degree‑2 branched covering F:S^2→S^2 via a Lattès-type quotient of a hyperbolic toral endomorphism and a local derived-from-Anosov modification at two fixed points; the complement K of the two attracting basins is a hyperbolic repeller, locally Cantor×interval, with dense leaves, hence indecomposable (Theorem 2) . The candidate solution follows the same blueprint (torus endomorphism A, quotient by x∼−x, symmetric modification, completely invariant basins, K locally Cantor×I with dense leaf), differing mainly in modifying on the torus before descending rather than modifying on the sphere; the paper later notes the constructed F lifts to the torus, making the two approaches essentially equivalent .

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The manuscript gives a concrete, well-motivated construction of a degree‑2 sphere branched covering with a completely invariant indecomposable continuum. The approach is natural (Lattès quotient + local surgery) and the indecomposability criterion is proved in a self-contained way. The results are correct and of interest to dynamics on surfaces and complex dynamics (topological models). Minor expository clarifications would enhance readability but do not affect correctness.