OpenAI reports positive area entropy for the standard map at large parameters

The standard sine map of the two-dimensional torus has positive metric entropy with respect to normalized area for every sufficiently large positive parameter.

Sources for this record

What was already known

The manuscript distinguishes positive entropy for the exact deterministic standard map and area measure from earlier results involving perturbation, noise, or hyperbolic sets of possibly zero area.

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

Proves a full parameter tail and therefore answers Sinai’s positive-parameter-measure conjecture.

Limitations

The parameter threshold is existential; this concerns the standard sine map and its normalized area measure.

Technical verification Formal (Lean 4)

OpenAI reports a Lean proof matching the selected claim.

Formal checking

The pinned OpenAI Lean scope note identifies this selected claim.

Checker
OpenAI-reported Lean 4 / Comparator
Scope
The standard sine map of the two-dimensional torus has positive metric entropy with respect to normalized area for every sufficiently large positive parameter.
Basis
Reported by the linked checker
Evidence source

Checking a formal statement does not establish that it matches the original problem.

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, prior-work, and scoped checking review for non-notifying local inclusion.

Read this published revision