Oct 6, 2026
Lean formalization in OpenAI math repository (Result 358)
Model / AI: OpenAI (unreleased)
machine-checked (formal proof)self-reported (formal proof)
OpenAI's internal frontier model proved and formalized in Lean the main result of 'A Three-Manifold Without Conjugate Points and Without a Nonpositively Curved Metric'. We construct a closed connected orientable smooth three-manifold that admits a smooth Riemannian metric without conjugate points but admits no smooth Riemannian metric of nonpositive sectional curvature.
Source read 2026-10-08. Cataloged from OpenAI's formalization.yaml (Family 358). The Lean development was not rebuilt locally.