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2407.10513

ON PAIRS OF SPECTRUM MAXIMIZING PRODUCTS WITH DISTINCT FACTOR MULTIPLICITIES

Victor Kozyakin

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

Audit review

The paper’s Theorem 2.5 asserts that for a τ-permutable pair {A,B} and any product M of length k, σ(τ(M)) = σ(M); if k is odd then M and τ(M) have different counts of A and B, hence no cyclic permutation of one can match a cyclic permutation of the other. Its Corollary 2.6 then states that if an odd-length M is spectrum maximizing, τ(M) is a distinct spectrum maximizing product with different factor counts. The proof given in Section 4.1 relies on the multiplicativity of τ(X) = S^{-1}XS and the consequent spectral invariance under similarity, and on the swapping of A- and B-counts under τ. The candidate solution reproduces precisely these steps: it shows τ(M) = S^{-1}MS, deduces spectral equality, notes the odd-length factor-count swap, and concludes the corollary about spectrum-maximizing products. This matches the paper’s statements and proof structure closely, so both are correct with substantially the same proof approach .

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The specific results audited (Theorem 2.5 and Corollary 2.6) are correct and clearly argued. The structural criterion (\$\tau\$-permutability) elegantly enforces non-uniqueness of odd-length SMPs with differing factor multiplicities. The exposition is concise; a few small clarifications (e.g., explicitly noting \$\tau(M)=S\^{-1}MS\$) would further aid readers. Overall, the contribution is technically sound and practically useful for constructing examples in the JSR/SMP literature.