The singleton hypergraph is extremal for the Isolation Lemma

Vance Faber, David G. Harris

For every nonempty inclusion-free hypergraph on n vertices, every d≥1 and arbitrary real edge offsets, Faber and Harris prove that at least n times the sum of j^(n−1) for j=0,…,d−1 assignments in [d]^n isolate a unique minimum edge. The n-singleton hypergraph attains equality.

Sources for this record

What was already known

The classical Isolation Lemma and later bounds were weaker; Faber and Harris conjectured the exact singleton-extremal count in 2018.

AI involvement AI-centered

Faber and Harris credit ChatGPT with helping discover the central fractional charging argument. They developed the proof and verified that argument independently.

ChatGPT helped discover the central fractional charging idea; the authors supplied the full proof.

Importance Notable

The fractional charging argument proves the exact conjectured count, including edge offsets.

Limitations

The authors supplied the full proof and independently checked the model-assisted charging argument. The ChatGPT interaction is not archived, so its exact share of proof development is not known.

Technical verification Formal (human)

Faber and Harris expressly report independent verification of the central argument.

Independent checking

Independent human verification of the model-assisted central argument in the final paper

Checker
Vance Faber and David G. Harris, author-reviewers
Scope
Fractional charging proof of the sharp first-layer bound and resulting singleton-extremal isolation count
Basis
Reported by the linked checker
Evidence source

Human understanding Full

The authors explain the charging method and both incoming and outgoing bounds.

Correction and publication history

2026-10-18 · publication

The model-assisted charging argument is central to the exact count; it is distinct from the paper’s broader monotone-objective extension.

Read this published revision