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2402.12229

Self-projective sets

Argyrios Christodoulou, Natalia Jurga

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

Audit review

The paper defines Λ_A via rank-one elements in R_G and proves Theorem 1.2: for irreducible G containing a proximal element, Λ_A is exactly the closure of attracting fixed points of proximal elements. The paper’s proof uses a cone argument and the Krein–Rutman theorem on sequences of the form A_n A A_n to obtain proximal elements with fixed points arbitrarily close to a prescribed point in Λ_A, after first showing the easy inclusion via λ−n A^n → π of rank one. These steps are explicitly stated in the survey (definition and theorem statement) and sketched in the proof of Theorem 1.2. The candidate solution proves the same theorem with a different perturbative argument: it perturbs a rank–one ρ ∈ R_G with tr ρ ≠ 0 and shows matrices sufficiently close to ρ are proximal with attracting lines close to P(Im ρ), then approximates ρ by k_n g_n with g_n ∈ G. This gives the desired density and completes both inclusions. Both arguments are coherent under the same hypotheses; they differ methodologically but reach the same conclusion. See Definition 1.1 and Theorem 1.2 for the statement, and the proof outline invoking λ−n A^n and the Krein–Rutman step for density in the paper’s treatment.

Referee report (LaTeX)

\textbf{Recommendation:} no revision

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The theorem audited is foundational in the survey's framework and is established with standard techniques. The exposition is concise and points to the literature where appropriate. The result underpins later developments in the paper and is correctly proved. Minor clarifications could further aid readers unfamiliar with the cone/Krein–Rutman method, but they are not essential for correctness.