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2109.10029

Random iteration on hyperbolic Riemann surfaces

Marco Abate, Argyrios Christodoulou

correcthigh confidence
Category
Not specified
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper’s Theorem 1.5 states exactly the two claims about left iterated function systems in Bloch domains—(i) every limit point is constant and (ii) convergence to a constant is equivalent to convergence of the unique fixed points—and derives them by combining a uniform contraction on Hol(X,Ω) (Proposition 2.3) with a general topological result (Theorem 3.1) for uniformly contracting sequences of maps; see Theorem 1.5 and its proof via Proposition 2.3 and Theorem 3.1 as summarized in Corollary 3.3 and Remark 3.2 . The candidate solution proves the same result directly by exhibiting an explicit uniform Lipschitz constant c = tanh(R(Ω,X)/2) using Schwarz–Pick, monotonicity of the Poincaré metric, and a computation on hyperbolic balls via reduction to Δ, then reproducing the (i) and (ii) conclusions. This matches the paper’s statements and logic but supplies a sharper, explicit constant that the paper does not spell out. No logical gaps were found in either argument. Hence, both are correct and essentially address the same theorem via different proofs.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The paper gives a correct, complete treatment of left iterated function systems on Bloch domains in hyperbolic Riemann surfaces, paralleling known results for right iteration and extending them in a coherent framework. The arguments are clear and rest on well-established tools (Schwarz–Pick, completeness, and a clean metric contraction principle). Minor improvements include stating an explicit contraction constant in terms of the Bloch radius and recalling a few standard metric computations.