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2211.04919

Thermodynamic formalism for general iterated function systems with measures

Jader E. Brasil, Elismar R. Oliveira, Rafael Rigão Souza

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

Audit review

The paper establishes P(ψ)=log ρ(B_q), existence of equilibrium states, and uniqueness of the X-marginal under Gâteaux differentiability with complete, self-contained arguments tailored to IFSm. It proves P≤log ρ(B_q) by exhibiting a positive eigenfunction h of B_q and testing g=h, and P≥log ρ(B_q) via a normalization/eigenfunction construction, then shows USC and compactness for existence, and uses convex subdifferential calculus for uniqueness (all within its stated hypotheses). By contrast, the model’s solution relies on an unqualified Collatz–Wielandt equality for positive operators on C(X) and on an entropy representation involving h^v−h^a that is neither the paper’s variational principle nor justified in this generality. It also mixes ψ(x,θ) potentials with the paper’s ψ(x) setting and invokes a Donsker–Varadhan inequality without checking the absolute continuity and measurability needed for J_x and h^a. Hence the model’s proof is incomplete/incorrect in key steps, while the paper’s results are correct as stated.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The paper builds a clear thermodynamic formalism for IFSm, proving a precise variational principle, existence of equilibrium states, and a differentiability-based uniqueness conclusion. The arguments are correct within stated hypotheses, and the presentation is largely self-contained. A few clarifications (assumptions for eigenfunction existence, notation around potentials) would improve accessibility.