Abstract

We generalize Voronoi's theory of perfect quadratic forms to generalized copositive matrices over a full-dimensional closed convex cone K, by introducing a K-copositive minimum and perfect K-copositive matrices. We consider a key feature of a given cone, which we call Interior Ryshkov (IR) property. Under this property the classical theory and its applications generalize nicely and we prove that rationally generated cones possess this IR property. For contrast, we give a detailed example of a simple cone without the IR property, showing various differences to the classical case. Moreover, this example yields connections to questions of number theory, in particular to Diophantine approximation and the Pell Equation. Finally, as an application, we give inner and outer polyhedral approximations for the generalized completely positive cone and a method to find rational certificates for (non-)membership in this cone.

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Audit summary

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.

Current report

Detailed mathematical audit

Generated August 18, 2026
01Statements3 reported findingsCorrect

The central existence and characterization results for generalized perfect matrices are correct. The proof of the cone-placement theorem uses the inverse congruence from the one printed, but that repair verifies the theorem without changing its statement. A noncentral introductory aside about completely positive cones needs the local correction recorded below and has no role in the results.

Theorem 2.11Correct

Existence of a perfect form adapted to a prescribed closed cone

Pages 5–7 · Theorem 2.11 · arXiv:2602.05841v2

Choose UGLn(Z)U\in\mathrm{GL}_n(\mathbb Z) whose positive coordinate cone lies inside the given full-dimensional closed convex cone KK, and start with a perfect form QQ whose minimal vectors have the nonnegative representatives supplied by the cited copositive result. The arithmetically equivalent form QK=UTQU1Q_K=U^{-T}QU^{-1} has minimal vectors UMin(Q)U\,\operatorname{Min}(Q) and hence places them in KK. Integral congruence preserves perfection. This independently verifies the statement; the manuscript prints the opposite congruence, which is recorded under proofs.

Theorems 4.1 and 6.1Correct

Rational cones and the outer characterization

Pages 9–16 · Sections 4 and 6 · arXiv:2602.05841v2

For rationally generated cones, simultaneous rational approximation can be performed inside the cone while retaining linear independence, which supplies the required integral transformations. The duality argument in the outer characterization correctly converts inequalities on cone-restricted minimal vectors into supporting hyperplanes of the generalized Ryshkov polyhedron.

Completely positive cone asideMinor formal correction · no status impact

The claimed equality criterion for CPK\mathrm{CP}^K is false

Page 3 · introductory discussion of CPK\mathrm{CP}^K · arXiv:2602.05841v2

The text says CPK=PSD\mathrm{CP}^K=\mathrm{PSD} only when K=RnK=\mathbb R^n. If KK is a closed halfspace through the origin, for example K=Rn1×R0K=\mathbb R^{n-1}\times\mathbb R_{\geq0}, then every vector vv has either vKv\in K or vK-v\in K, and vvT=(v)(v)Tvv^T=(-v)(-v)^T. Every positive-semidefinite matrix therefore has a rank-one decomposition using vectors in KK, so CPK=PSD\mathrm{CP}^K=\mathrm{PSD} although KRnK\neq\mathbb R^n. Deleting or weakening this unused introductory sentence is the complete local repair; no theorem or proof depends on it.

02Proofs2 reported findingsContains incorrect or incomplete proofs

The proof of Theorem 2.11 contains a reversed integral congruence. The theorem is repairable by replacing that congruence with its inverse transpose, but the proof is not correct as printed. The remaining central proof chains are complete.

Proof of Theorem 2.11Incorrect as written

The printed congruence moves minimal vectors in the wrong direction

Pages 6–7 · proof of Theorem 2.11 · arXiv:2602.05841v2

The chosen matrix UU satisfies UR+nKU\mathbb R_+^n\subset K. For the printed form UTQUU^TQU, however, the minimal vectors are U1Min(Q)U^{-1}\operatorname{Min}(Q), and the construction gives no reason for those vectors to lie in KK. Replacing the displayed form by UTQU1U^{-T}QU^{-1} makes its minimal vectors UMin(Q)U\operatorname{Min}(Q) and proves the desired inclusion. This is a verified repair of the proof, so the theorem itself remains classified as correct.

Sections 4–6Correct and complete

Cone approximation and polyhedral duality

Pages 9–16 · arXiv:2602.05841v2

The approximation stays in the relative interiors needed for the cone constraints, the resulting integer matrices remain nonsingular, and the finiteness argument is applied only after normalizing the relevant minima. The supporting-functional argument then establishes both inclusions of the outer description.

03Novelty0 reported findingsNo non-novelty findings

No non-novelty findings.

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Paper
arXiv:2602.05841v2
Authors listed
Alexander Oertel, Achill Schürmann
Audit date
August 18, 2026
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