OpenAI reports the metric Blaschke classification

Every connected closed smooth Riemannian manifold of positive dimension whose global injectivity radius equals its diameter is, up to scale and isometry, a standard compact rank-one symmetric space.

Sources for this record

What was already known

Metric Blaschke classification was known for the circle, sphere and real-projective types. The remaining complex, quaternionic and Cayley-plane cases required additional rigidity, particularly in higher quaternionic dimensions.

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

Resolves the metric Blaschke conjecture in all dimensions and model types.

Limitations

The hypothesis is equality of global injectivity radius and diameter; the conclusion includes the round sphere and standard real, complex, quaternionic projective spaces and Cayley plane.

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; technical verification remains Reported.

Read this published revision