Vu-Le reports: uniqueness and stability of Gerver’s moving sofa

The-Anh Vu-Le’s project reports that Gerver’s sofa is the unique area-maximizing moving sofa up to rigid motion, and that sofas with area deficit ε are within C√ε after translation in its Hausdorff-distance model, with exponent 1/2 optimal.

Sources for this record

What was already known

Baek’s 2024 paper established optimality. The project identifies uniqueness as a separate target and adds quantitative stability; the ambidextrous left-and-right-turning sofa problem is a different statement.

AI involvement AI-led

Vu-Le directed the project. ChatGPT Pro 6 produced the uniqueness, stability and coercive-certificate arguments; Claude Opus 5.5 completed and repaired their Lean proofs while retaining credited human prior work.

The contribution log credits models with the new uniqueness, stability and coercive-certificate mathematics, including model repairs; Baek’s earlier optimality remains prior human work.

Importance Major

Strengthens a known geometric optimum into uniqueness and a quantitative description of near-optimal shapes.

Limitations

The result uses the project’s continuous-motion definitions and its coercive certificate built from Baek’s framework. No human has reviewed the proof, statements or definitions according to the disclosure. This record concerns version 5’s ordinary moving-sofa results, not the already covered ambidextrous optimum. AIProofWatch has not rebuilt the formal development or audited the complete proof. Palomar reports mechanical checking of a pinned statement; its automated statement review is not human peer review. The reported date records this registry checkpoint; the earlier first-report date of the formalization has not been established.

Technical verification Formal (Lean)

A completed rigorous check is documented for the scoped statement. Palomar: Lean, NanoDa and con-ron (reported): Baek.gerver_sofa_unique, gerver_sofa_stable, gerver_sofa_stability_exponent and the recorded bridge/certificate declarations in version 5 at 1174c5c25c1c66b807e368446d6682e8d0276759; three standard Lean axioms.

Formal checking

Registry-reported Comparator and kernel checking; not reproduced by AIProofWatch.

Checker
Palomar: Lean, NanoDa and con-ron (reported)
Scope
Baek.gerver_sofa_unique, gerver_sofa_stable, gerver_sofa_stability_exponent and the recorded bridge/certificate declarations in version 5 at 1174c5c25c1c66b807e368446d6682e8d0276759; three standard Lean axioms.
Basis
Reported by the linked checker
Check date
2026-10-07
Evidence source

Checking a formal statement does not establish that it matches the original problem.

Human understanding Few

Few is the default when evidence for a higher level is insufficient. No sufficient account of a named human explaining the scoped central reasoning is established in this assessment. Missing disclosure is not evidence of little understanding.

Correction and publication history

2026-10-14 · publication

Source-statement, baseline, AI-role and verification-scope review, 14 October 2026. New curated contribution; eligible for matching consented digests.

Read this published revision