AI-found graph refutes Graffiti Conjecture 806 on a distinct-degree reading

For PR[S] on square-free integers S⊂[2,n], with edges where gcd exceeds one, the n=51 graph has an exact integer Rayleigh witness showing its largest adjacency eigenvalue exceeds its number of distinct degree values.

Sources for this record

What was already known

Fajtlowicz’s Written on the Wall I conjecture 806 asserted the inequality; its block preamble says the family had been tested through n≤100 and roughly twenty more values through 200. The n=51 example contradicts that empirical baseline.

AI involvement AI-led

The AI Village repository credits Claude Opus 5 as agent author of the graph construction and exact verifier; no run record establishes full autonomy.

The AI Village agent is credited with the result and verifier; no individual run record establishes stronger autonomy.

Importance Modest

Gives a finite counterexample to Graffiti Conjecture 806 under the distinct-degree interpretation.

Limitations

The original wording about vertices of different degrees is ambiguous without its surrounding text. The finite witness does not establish the repository’s broader asymptotic claims.

Technical verification Formal (exact integer computation)

The n=51 counterexample is certified by an exact integer Rayleigh inequality in the source verifier. This is a source-reported finite machine check, not a reproduced run or a proof of asymptotic claims. VibeMathed reports independently rerunning the verifier on 2 September 2026, but the primary-text fidelity option was unavailable.

Formal checking

Constructs an integer vector, computes xᵀAx and xᵀx exactly, and checks xᵀAx>d·xᵀx

Checker
AI Village Python verifier verify_wow1_806.py
Scope
At n=51, λ₁(PR[S]) exceeds the number of distinct degrees
Basis
Reported by the linked checker
Evidence source

Formal checking

VibeMathed reports rerunning the exact integer verifier on 2 September 2026; fast and full modes passed their assertions. The primary-text file was unavailable to its optional fidelity check.

Checker
VibeMathed verification report
Scope
n=51 exact Rayleigh counterexample under the distinct-degree graph reading
Basis
Reported by the linked checker
Check date
2026-09-02
Evidence source

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

Human understanding Few

The code explains its finite certificate, but no named human explains the result; Few is the evidence default.

Correction and publication history

2026-10-18 · publication

Gives a finite counterexample to Graffiti Conjecture 806 under the distinct-degree interpretation.

Read this published revision