The codimension-one bound for singular sets of stationary integral varifolds
Let be a stationary integral -varifold in an open set and the support points near which is not an integer multiple of one smooth embedded minimal submanifold. Two -planes meeting along an -plane form a stationary varifold whose singular set is -dimensional, so no better bound is possible. Known cases included two-valued stationary Lipschitz graphs (Hirsch-Spolaor) and classes with controlled density under an epsilon-regularity assumption (Krummel-Minter-Wickramasekera). Brena, Decio and De Lellis (2025, Conjecture 1.1) conjecture the sharp bound, which is stronger than almost-everywhere regularity. Does every stationary integral -varifold satisfy , in every dimension and codimension?
- Result
- Proved(see note)
- Status
- Candidate (review pending)
- AI contribution
- AI-discovered
- Method
- Argument
- Field
- Geometric measure theory: regularity of stationary varifolds
- Posed by
- Camillo Brena, Stefano Decio and Camillo De Lellis, Remarks and conjectures on stationary varifolds dedicated to Enrico Bombieri, Rend. Lincei Mat. Appl. 36 (2025), Conjecture 1.1
- Year posed
- 2025
- Years open
- 1y
- Solved
- 2026-10-05
- 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: for every stationary integral -varifold in an open , , , with no stability, minimizing, orientability, density or codimension hypothesis; crossing planes show it is sharp. This implies . The proof combines the companion paper's signed-excess estimates with a fitting and frequency analysis around a smooth center and a measure-valued blow-up at higher-multiplicity planar tangents. It does not prove rectifiability or finer structure of the singular set, and does not cover Riemannian ambient metrics.
What the AI did
The OpenAI math release (github.com/openai/math, commit adc7f12) states that its results were produced by an unreleased internal OpenAI model under one fixed procedure, averaging about three hours of ChatGPT Pro thinking compute per result, across roughly 4,000 posed problems; outputs were then grouped into families and filtered for significance. This result is not among the README's stated exceptions (the Riemann zeta zero-free region work and the Hodge conjecture for CM abelian varieties). The manuscript is credited to OpenAI alone and names no human author. The README also cautions that unformalized results could have issues.
Verification
No independent mathematician has checked this yet. Checked here: the abstract, introduction and Theorem 1.1 of the TeX source, read against Conjecture 1.1 of Brena-Decio-De Lellis as the manuscript quotes it; the proof was not refereed. The proof imports the signed-excess theorem and local estimates of the companion almost-everywhere regularity manuscript from the same release, itself unreviewed, so a gap there would carry over. Euclidean ambient space only. The release has no Lean formalization for this family, and the README cautions that unformalized results could have issues.