arXiv:0904.1906v2

On Diophantine approximations with positive integers: a remark to W.M.Schmidt's theorem

Nikolay G. Moshchevitin

math.NT11J13

Abstract

We prove a generalization of W.M. Schmidt's theorem related to Diophantine approximations for a linear form of the type α1x1+α2x2+yα_1x_1+α_2x_2+y with positive integers x1,x2x_1,x_2.

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Audited against arXiv v2

Not a correctness certificate. A “Correct” result may include yellow typos or minor formal corrections that do not affect substantive soundness. It means this audit found no unresolved substantive error under the stated criteria; it does not replace expert scrutiny or formal verification.

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Generated August 20, 2026
01Statements2 reported findingsCorrect

The quantitative positive-coordinate approximation theorem and its local best-approximation alternative are correct; a verified repair is needed in the printed proof of Lemma 1.

Theorem 2Correct

Positive-coordinate approximation under a Diophantine lower bound

Pages 1–3 · Theorem 2 and its reduction to Theorem 3 · arXiv:0904.1906v2

The alternatives of Theorem 3 provide infinitely many positive integer pairs. Combining ΓMνγMν+12\Gamma M_\nu^{-\gamma}\leq M_{\nu+1}^{-2} with alternative (ii) gives the displayed lower bound for MνM_\nu in terms of the positive solution size; substitution into its error estimate yields exactly g(γ)=τ+(2τ2)/(τ2γ2)g(\gamma)=\tau+(2\tau-2)/(\tau^2\gamma-2) and the stated constant C(Γ)C(\Gamma).

Theorem 3Correct

Local alternative for three independent best approximations

Page 3 · Theorem 3 · arXiv:0904.1906v2

Corollaries 1–3 exhaust the cases determined by ζν+1\zeta_{\nu+1} and ζν\zeta_\nu. Their size bounds imply the common upper bound in alternative (ii), while the golden-ratio identity τ1=1/τ\tau-1=1/\tau gives the stated exponent. The repair to Lemma 1 below supplies its required positive point without changing any constant.

02Proofs4 reported findingsContains incorrect or incomplete proofs

Lemma 1 makes an invalid equality-boundary inference as printed. A verified local perturbation repairs it and preserves all theorem statements and constants.

Lemma 1Incomplete as written · verified repair

Minkowski at the critical volume does not itself give strict inequalities

Page 4 · proof of Lemma 1 · arXiv:0904.1906v2

The closed parallelepiped has volume exactly 88, so Minkowski supplies a nonzero lattice point only with non-strict boundary inequalities. Linear independence excludes a zero linear-form value, but it does not exclude α1x1+α2x2+y=ζν|\alpha_1x_1+\alpha_2x_2+y|=\zeta_\nu, nor does it by itself force both x1,x2x_1,x_2 to be nonzero. Thus the printed sentence claiming strict positivity and strict error directly from linear independence is not valid. Verified repair: for 0<ε<10<\varepsilon<1, replace the error and difference bounds by (1ε)ζν(1-\varepsilon)\zeta_\nu and (1ε)Mν+1(1-\varepsilon)M_{\nu+1}, and replace RνR_\nu by Rν/(1ε)2R_\nu/(1-\varepsilon)^2; the volume remains 88. The resulting point has strict error, hence lies outside the earlier best-approximation body and has maxxiMν+1\max|x_i|\geq M_{\nu+1}; the strict difference bound forces the two coordinates to have the same nonzero sign. Taking a sequence ε0\varepsilon\downarrow0, boundedness gives one repeated lattice point, which has maxxiRν\max|x_i|\leq R_\nu and the same strict error and sign properties. Negating it if necessary proves Lemma 1 with every printed constant.

Lemma 1 notationTypo

Two subscripts name the wrong bodies

Page 4 · proof of Lemma 1 · arXiv:0904.1906v2

Replace RμR_\mu by RνR_\nu in the volume identity and replace Ω2Ω1\Omega_2\setminus\Omega_1 by Ων1Ων\Omega_\nu^1\setminus\Omega_\nu. The definitions on the same page uniquely determine both corrections.

Lemma 2Correct and complete

Lattice-basis and coefficient bounds

Pages 5–6 · Lemma 2 and Equations (6)–(8) · arXiv:0904.1906v2

The nonzero integer determinant and the two small-error hypotheses give DνMν2/2D_\nu\geq M_\nu^2/2. Minkowski's second-minimum argument in the lattice generated by ξν,ξν+1\xi_\nu,\xi_{\nu+1} produces an independent point within the thin rectangle; its perpendicular coefficient is one in absolute value, so it and ξν\xi_\nu form a lattice basis. The translated fundamental-domain bound then gives the positive point and the displayed coefficient and error estimates.

Proof of Theorem 3Correct and complete

The three corollaries cover every case

Pages 6–7 · proof of Theorem 3 · arXiv:0904.1906v2

If ζν+1(8Mν+22)1\zeta_{\nu+1}\geq(8M_{\nu+2}^2)^{-1}, Corollary 1 gives alternative (i). Otherwise the second hypothesis of Lemma 2 holds, and the two complementary ranges of ζν\zeta_\nu invoke Corollary 2 or Corollary 3. Their bounds imply alternative (ii) because Mν+1τ1Mν1/τM_{\nu+1}^{\tau-1}\geq M_\nu^{1/\tau}.

03Novelty0 reported findingsNo non-novelty findings

No non-novelty findings.

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Paper
arXiv:0904.1906v2
Authors listed
Nikolay G. Moshchevitin
Audit date
August 20, 2026
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