OpenAI reports a complex Lipman–Zariski counterexample

There is a singular normal integral affine surface over the complex numbers whose tangent module is free of rank two on the whole surface.

Sources for this record

What was already known

The Lipman–Zariski conjecture predicted smoothness from a locally free tangent sheaf. Positive cases included characteristic-zero hypersurfaces and local complete intersections, log-canonical spaces, and isolated singularities in dimension at least three; positive-characteristic surface counterexamples did not settle the complex case (manuscript introduction, pp. 1–2).

AI involvement AI-led

OpenAI credits itself as manuscript author and states that its internal frontier model produced the results in this release. Individual human input is not detailed enough to establish task-only autonomy.

OpenAI is named as author on the manuscript, and its release attributes the results to an internal frontier model. The individual human input is not detailed enough to establish autonomy.

Importance Major

Disproves the characteristic-zero Lipman–Zariski conjecture in the first dimension left by the cited isolated-singularity result.

Limitations

The example is a normal complex affine surface, smooth away from one marked singular point. It does not make a claim about hypersurfaces or log-canonical singularities.

Technical verification Reported

Reported is the default when evidence for a higher level is insufficient. The OpenAI-authored manuscript reports and argues the result, but the reviewed sources do not document a completed check of the full assessed claim.

Human understanding Few

Few is the default when evidence for a higher level is insufficient. No named person is documented as explaining the central argument for this assessed contribution.

Correction and publication history

2026-10-18 · publication

Primary manuscript, attribution, and prior-work review for non-notifying local inclusion.

Read this published revision