The Global Spherical Shell conjecture for minimal class VII surfaces with positive second Betti number
A compact complex surface is of class VII if and its Kodaira dimension is ; these are the non-Kahler surfaces left open by the Enriques-Kodaira classification. With the minimal ones are Hopf and Inoue surfaces (Bogomolov, Li-Yau-Zheng, Teleman). A global spherical shell is a holomorphic embedding of a neighborhood of with connected complement; Kato showed surfaces with one are degenerations of blown-up Hopf surfaces. Nakamura's classification program conjectures (Working Hypothesis 5.5) that shells always exist when ; Teleman proved it for , and Dloussky-Oeljeklaus-Toma reduced it to finding rational curves. Does every minimal class VII surface with contain a global spherical shell?
- Result
- Proved(see note)
- Status
- Candidate (review pending)
- AI contribution
- AI-discovered
- Method
- Argument
- Field
- Complex geometry; non-Kahler compact complex surfaces of class VII
- Posed by
- Iku Nakamura (Working Hypothesis 5.5, Sugaku 36, 1984)
- Year posed
- 1984
- Years open
- 42y
- Solved
- 2026-09-24
- Model
- Unreleased internal OpenAI model
- Vendor
- OpenAI
- Collaborators
- —
- Verification
- Unreviewed
- Publication
- Announced
- Collection
- OpenAI math release (October 2026), version adc7f12
- Significance
- 50 / 100
- Disclosed cost
- —
- Wikipedia
- No dedicated article
What was actually shown
Theorem 1.1: every minimal class VII surface with contains a global spherical shell. Corollaries: by Kato, each such surface deforms to blown-up primary Hopf surfaces, has and is diffeomorphic to ; and aspherical compact complex surfaces satisfy . The proof builds divisors on the infinite cyclic cover and shows all their components are compact rational curves, then applies Dloussky-Oeljeklaus-Toma. It does not give a complete biholomorphic classification of the resulting Kato surfaces beyond what Kato's theory provides.
What the AI did
The release README says every result in openai/math was produced by an unreleased internal OpenAI model with a fixed procedure, on average about three hours of ChatGPT Pro thinking compute per result. This result is not one of the README's two exceptions (the Hodge conjecture for CM abelian varieties and the Re(s) > 11/12 zero-free region). The manuscript is authored 'OpenAI' and names no human author.
Verification
No independent mathematician has checked this yet. Checked here: Theorem 1.1 was read against Nakamura's Working Hypothesis 5.5; it is stated for every connected compact complex surface with , , and no -curve, and gives a global spherical shell. The proof was not refereed. No Lean formalization of this manuscript is in the release (there is no lean/docs/060.md at the pinned commit). The argument relies on Enoki's theorem and the Dloussky-Oeljeklaus-Toma criterion, both published, and constructs the needed rational curves on the infinite cyclic cover by weighted Fourier-Laplace analysis.