OpenAI reports perfect completeness for 2-to-1 games

For every fixed rational 0<δ<1, it is NP-hard to distinguish satisfiable 2-to-1 games from unweighted games of value at most δ, with an alphabet depending only on δ.

Sources for this record

What was already known

The 2-to-1 Games Conjecture with perfect completeness had remained open; prior hardness reductions did not establish this full value gap from satisfiable instances.

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

Settles the perfect-completeness 2-to-1 Games Conjecture, a central constraint-satisfaction hardness question.

Limitations

The statement uses a fixed rational soundness parameter and a fixed alphabet for that parameter. OpenAI reports the Lean check; it was not rerun here.

Technical verification Formal (Lean 4)

OpenAI reports a Lean proof matching the selected claim.

Formal checking

The pinned Lean note covers a deterministic polynomial-time reduction from binary 3SAT to nonempty unweighted 2-to-1 games with the stated completeness and soundness.

Checker
OpenAI-reported Lean 4 / Comparator
Scope
For every fixed rational 0<δ<1, it is NP-hard to distinguish satisfiable 2-to-1 games from unweighted games of value at most δ, with an alphabet depending only on δ.
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