arXiv:1310.6691v1
Abstract
We prove a conjecture due to Nicolas Chevallier concerning unimodular matrices related to simultaneous Diophantine approximation to real numbers.
AI-generated audit
Audit summary
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.
Current report
Detailed mathematical audit
01Statements2 reported findingsCorrect
The construction answering Chevallier's question and the companion existence theorem for unimodular approximation triples are supported by the paper's nested-cone and best-approximation arguments.
The obstruction to uniformly good unimodular triples is verified
Sections 1 and 3-5 · Theorem 1, Proposition 2, and the inductive construction · arXiv:1310.6691v1
The construction chooses nested cones and complete rank-two lattices so that every sufficiently accurate integer vector belongs to the current plane. Lemma 5 then forces any third vector completing a unimodular matrix to have error bounded below by the prescribed scale. Choosing the scales against the given decreasing function yields Theorem 1, while the same determinant obstruction gives Proposition 2.
Unimodular triples with errors tending to zero exist for every independent pair
Sections 1 and 6 · Theorem 2 · arXiv:1310.6691v1
Each consecutive pair of best approximations spans a complete rank-two lattice and can be extended to a basis of . Projecting its fundamental parallelogram to the neighboring affine lattice plane gives an integer point completing the pair to a unimodular triple. The projection offset equals the reciprocal covolume and tends to zero by the cited covolume-error relation, so all three approximation errors tend to zero.
02Proofs3 reported findingsCorrect
The geometric induction and determinant estimates close the stated arguments. A few coordinate symbols are evident typos and do not change any conclusion.
The cone and complete-lattice induction preserves all invariants
Sections 2-4 · Lemmas 1-4 and conditions (i)-(viii) · arXiv:1310.6691v1
The local cone lemmas provide an open neighborhood in which the designated lattice vectors remain consecutive best approximations. Lemma 4 supplies the next primitive vector and complete plane, while the shrinking diameters give a limiting vector with the required rational independence.
The determinant lower bound is valid after two mechanical symbol repairs
Section 5 · Lemma 5 and its displayed determinant · arXiv:1310.6691v1
Expanding the nonzero integral determinant in the two approximation-error coordinates gives the claimed lower bound once the third entry in the first row is read as rather than , and the last entry is read as . The parallel rows uniquely determine both corrections.
Two mismatched coordinates are typos
Section 5 · determinant in the proof of Lemma 5 · arXiv:1310.6691v1
The repeated in the third error coordinate must be , and must be . Both are isolated notation mismatches; the subsequent norm estimate uses the corrected two-coordinate vector.
03Novelty0 reported findingsNo non-novelty findings
No non-novelty findings.