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2212.01932

Some applications of the minimal model program in arithmetic dynamics

Brett Nasserden

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

Audit review

The paper’s criterion (Theorem 7.6) that λ1(f) > 1 if and only if [f] has infinite order in π0Aut(X) for normal projective X with finitely generated nef cone is correct and is proved via a robust group-theoretic construction (D(X)) and a homomorphism Lin with finite kernel. The candidate solution reaches the same conclusion but its key converse step contains a gap: it deduces a_i ≥ 1 by asserting λ1((f^m)^{-1}) = 1 from λ1(f^m) = 1, which is not generally valid in higher dimensions. This flaw can be repaired by using det(f^{m*}) = ±1 on N^1(X)Z (so ∏ a_i = 1 and, with max a_i ≤ 1, all a_i = 1), as effectively done in the paper’s Proposition 7.5 argument.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The paper gives a clean MMP-based approach to several questions in arithmetic dynamics. The Section 7 criterion linking positive entropy to the component group is conceptually illuminating and well-executed via the subgroup D(X) and the homomorphism Lin. The exposition is largely clear; a few linear-algebraic points (determinant/eigenvalue discussion) could be made more explicit to aid readers. Overall, strong and publishable after minor polishing.