arXiv:0906.1541v2
Abstract
We give an elementary proof of a recent metrical Diophantine result by D. Kleinbock related to badly approximable vectors in affine subspaces.
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Detailed mathematical audit
01Statements3 reported findingsCorrect
The metric theorem is correct under its intended finite-scaling hypotheses. Corollary 2 needs the same logarithmic parameter restriction already used in Corollary 1.
Metric transfer from a badly approximable subspace
Page 2 · Theorem 1 · arXiv:0906.1541v2
The covering estimate gives a cumulative lattice-point count . Partial summation against and the assumed convergence of make the exceptional limsup set null, proving that almost every point of is -badly approximable.
The scaling supremum must be finite
Page 2 · Equation (5) and Theorem 1 · arXiv:0906.1541v2
Replace by , equivalently a positive lower bound for for each fixed . The printed comparison with is vacuous, while the Borel–Cantelli reduction needs exactly this fixed-scale lower comparison when . The surrounding analogous condition (4) and the use on page 4 determine the correction.
The range and the exponent should be displayed
Page 2 · Corollary 2 · arXiv:0906.1541v2
State and define . Equation (7) is written with exponent for Corollary 1, so merely referring to it leaves the -dimensional specialization and its necessary range unstated. With this local substitution, and the series converges exactly in the displayed range. No later statement depends on a different range.
02Proofs2 reported findingsCorrect
The lattice covering, Borel–Cantelli, and partial-summation steps are correct after the explicit scaling-notation correction.
Covering count for integer points
Pages 2–3 · construction of , , and Equation (9) · arXiv:0906.1541v2
After ordering two lattice points by their zeroth coordinate, their difference lies in . Thus every translate of contains at most one lattice point. Comparing the transverse widths of and yields translates.
The exceptional sets have summable measure
Pages 3–4 · Equations (11)–(12) · arXiv:0906.1541v2
Each height- lattice point contributes an -dimensional ball of radius comparable to . Dyadic decomposition of Equation (9) gives , since monotonicity of supplies a geometric factor . Abel summation then converts the series to , with the boundary term tending to zero.
03Novelty0 reported findingsNo non-novelty findings
No non-novelty findings.