VibeMathedMath problems solved by AI

Erdős Problem #387

Erdős and Graham asked whether (nk)\binom{n}{k} with 1kn/21 \le k \le n/2 must always have a divisor n\le n that is close to nn, meaning bigger than a fixed constant times nn. Settled in both directions: true when kk is large enough as a function of nn, but false in general, since there are (nk)\binom{n}{k} with kk small compared to nn having no such divisor.

Result
Disproved(see note)
Status
Resolved
AI contribution
AI co-developed
Method
Argument
Field
Number theory
Posed by
Paul Erdős, Ronald Graham
Year posed
Years open
Solved
2026-05-20
Model
ChatGPT 5.5 Pro
Vendor
OpenAI
Collaborators
Hung M. Bui, Slava Naprienko, Kyle Pratt, Alexandru Zaharescu
Verification
Unreviewed
Publication
Preprint
Significance
35 / 100
Disclosed cost
Wikipedia
No dedicated article

What was actually shown

false in general; the positive direction holds for k large relative to n

What the AI did

The disclosure is carefully scoped rather than blanket. The main ideas in the proof of Theorem 5.1 were developed in interactive sessions between the authors and ChatGPT 5.5 Pro, and some documents and code in the accompanying repository were generated with AI assistance. The authors separately used ChatGPT for literature searches and for spotting typos, and they state that all text in the paper is human-generated. The heavier half of the paper, a restricted covering problem attacked with sieve methods and exponential sum estimates, is presented as the authors' own.

Verification

arXiv preprint, not peer-reviewed. The authors credit the model with the main ideas of one theorem rather than the paper, so the bulk of the argument rests on ordinary refereeing.

Source

arXiv:2605.21221 - Binomial coefficients with divisors avoiding an interval

Discussion