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2109.02378

Limit laws in the lattice problem. II. The case of ovals.

Julien Trevisan

correcthigh confidence
Category
math.DS
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper proves a limit law for the normalized lattice point error in dilated ellipses for a random unimodular lattice and derives moment properties of the limiting law (Theorem 1). Its structure is: reduction to the disk via an SL2 change of variables; Poisson summation with Bessel asymptotics to express R(tE,L)/sqrt(t) in terms of dual lattice lengths; a truncation/regularization step that reduces to a prime-sum with multiplicities; an independence/equidistribution-in-the-limit result for the phases t||k1 e1 + k2 e2|| (mod 1); and finally an almost-sure convergence and moment analysis for a modified Siegel transform with random weights, giving the same limit law and its properties . The candidate solution outlines the same overall program and arrives at the same limit distribution S(θ,L) with the same properties (i)–(v). Its equidistribution step uses a coarea-formula/absolute-continuity argument rather than the paper’s “geodesic segment + Z-freeness of first-order coefficients” route, so the approaches differ in technique but are compatible in conclusion . Two minor issues in the candidate: (1) a transient normalization mismatch in the Poisson–Bessel constant when summing over all nonzero dual vectors (the paper’s 1/π over L⊥ leads, after grouping by primes and restricting to P^+, to the 2/π in S; the model’s final constant matches the paper’s S but its intermediate display had 2/π at the “all vectors” level) ; and (2) an over-optimistic bound for Eθ|S|^2 in terms of ||L||1 that ignores dominance by the shortest vector near the cusp. This bound is used only heuristically; the model ultimately states the correct moment threshold p<4/3 and the non-existence of the 4/3-moment on sets with σ(L) bounded below and ||L||1<α, which agrees with the paper’s sharp heavy-tail analysis . Overall, both arguments are correct; the paper’s proof is more detailed and rigorous on technical points like regularization and variance control, whereas the model’s proof sketch is briefer and swaps in a standard coarea-based route for equidistribution.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The paper establishes a precise limit law for the normalized lattice point error for random lattices in the oval case and derives sharp moment bounds, including the exact 4/3 threshold. The proof is technically clean: smoothing and Poisson–Bessel asymptotics, an independence-at-infinity mechanism, and a careful random-weights model culminating in almost sure convergence and moment control. Clarifying normalizations and consolidating the independence argument would make the exposition even clearer.