OpenAI reports the dyadic Erdős similarity case

For every eta in (0,1), there is a compact subset of [0,1] of measure greater than 1−eta that contains no affine copy of {2^(−n):n>=1} under any translation or nonzero real dilation of either sign.

Sources for this record

What was already known

Earlier nonuniversality results covered sequences whose consecutive ratios tend to one and patterns with stronger additive structure. The single dyadic sequence has persistent geometric gaps and was not covered by those criteria (companion manuscript introduction, Related results, pp. 1–2).

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 Notable

Proves that the dyadic sequence is not measure universal, a geometric-progression case of the Erdős similarity conjecture.

Limitations

The selected theorem treats only ratio 1/2. The first manuscript’s assertion for every fixed ratio q in (0,1), and the full conjecture for arbitrary infinite sets, are outside the Lean scope.

Technical verification Formal (Lean 4)

OpenAI reports a Lean proof matching the selected claim.

Formal checking

The pinned Lean note formalizes compact near-full-measure dyadic avoidance for every translation and nonzero dilation, including both signs.

Checker
OpenAI-reported Lean 4 / Comparator
Scope
For every eta in (0,1), a compact set E subset [0,1] of measure greater than 1−eta contains no affine copy of {2^(−n):n>=1} for any translation and nonzero real dilation.
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 companion manuscript, attribution, prior-work, and exact Lean-scope review for non-notifying local inclusion.

Read this published revision