Short proofs in combinatorics, probability and number theory II

Boris Alexeev, Moe Putterman, Mehtaab Sawhney, Mark Sellke, Gregory Valiant

For integers r≥3, k≥4 and n≥72, the maximum ordinary-line count Fᵣ,ₖ(n) is at least n²/12−(10/3)n. The elliptic-curve construction has no four collinear points and a bipartite ordinary-line graph.

Sources for this record

What was already known

Erdős expected a subquadratic maximum. Earlier no-four-collinear constructions avoided ordinary triangles but lacked a quadratic ordinary-line count.

AI involvement AI-led

An internal OpenAI model supplied the elliptic-curve coset construction and proof. Alexeev, Putterman, Sawhney, Sellke and Valiant checked and explained it.

The central construction and original proof are credited to the internal model; the exact prompting history is not disclosed.

Importance Notable

Disproves the subquadratic expectation, including the r=3 and k=4 boundary case.

Limitations

The five human coauthors report checking the model solution and explain its mechanism. No separate machine certificate or third-party verification is documented.

Technical verification Formal (human)

The human coauthors explicitly report verifying each model solution; this is source-reported full human verification, not a machine formalization or an AIProofWatch rerun.

Formal checking

The human coauthors explicitly report verifying each model solution; this is source-reported full human verification, not a machine formalization or an AIProofWatch rerun.

Checker
Alexeev, Putterman, Sawhney, Sellke and Valiant
Scope
Problem 960 elliptic-curve ordinary-line construction, including r=3 and k=4
Basis
Reported by the linked checker
Evidence source

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

Human understanding Full

The authors give and interpret the elliptic-curve group-law, coset bipartition, and edge-count mechanism.

Correction and publication history