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2506.19362

Sturmian lattices and Aperiodic tile sets

Shigeki Akiyama, Tadahisa Hamada, Katsuki Ito

correctmedium confidence
Category
Not specified
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper formalizes the projective simplex Δ of tile ratios, the Veronoi curve TVC(α) = [(1−α)^2:2α(1−α):α^2], and the SAB matching rule, showing that any realizable tiling must lie in TA ∩ TVC where TA is the convex hull of finitely many rational points arising from patch-tiles . It proves the trichotomy: (1) rational α are enforced by a singleton A = {T}, (2) quadratic α by two tiles via a rational line orthogonal to n(α) (constructed from the minimal polynomial), and (3) no finite A enforces non-quadratic α; the argument reduces to intersections of a rational polygon with the conic TVC and the fact that a line meets a conic in at most two points, yielding only rational or quadratic parameters on edges and an arc with rational points in interiors . The candidate solution mirrors this geometry: Δ, TVC as a conic, enforcement as TA ∩ TVC = {TVC(α)}, the rational line cut for quadratic α using the minimal polynomial, and the impossibility for non-quadratic α via tangency considerations. It adds a standard (but nonessential) remark about an inflation coming from an SL(2,ℤ) matrix with eigenvalue a quadratic unit. Net: same core proof idea; the paper supplies full hypotheses (matching rule, density computation) and a constructive orthogonality criterion n(α), while the model provides essentially the same proof in slightly different language. The conclusions match exactly.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper develops a crisp geometric framework in projective coordinates to classify which slopes are enforceable by finite patch-tile sets under the SAB rule, and it executes a clear proof of the resulting trichotomy. The constructions for quadratic slopes are convincing and illustrative, and the overall exposition is accessible. Minor presentational tweaks would make the key algebra–geometry bridge (minimal polynomial to rational line orthogonal to TVC) even more transparent.