The perfect 1-factorisation conjecture holds asymptotically

Yangyang Cheng, Amedeo Sgueglia

For every ε>0 and all sufficiently large even n, the complete graph K_n contains at least (1−ε)n edge-disjoint perfect matchings such that every pair forms a Hamilton cycle. This is the model-origin construction of Theorem 1.3.

Sources for this record

What was already known

Kotzig’s conjecture asks for all n−1 matchings in a perfect 1-factorisation to have this property. Earlier constructions covered special orders or smaller partial families.

AI involvement AI-centered

ChatGPT 5.4 generated the rotating-matching construction and an initial proof. Cheng and Sgueglia found a different shorter proof and alone developed the completion to a full factorisation.

The model supplied the retained asymptotic matching construction, while the stronger factorisation theorem and final proofs are human.

Importance Notable

Gives an asymptotically complete pairwise-perfect collection for every large even order.

Limitations

The stronger full factorisation in Theorem 1.2 and its probabilistic completion are human results. The authors replaced the initial model proof with a shorter human proof; the original proof is unavailable for comparison.

Technical verification Formal (human)

The authors call the initial model proof correct and give their own complete proof of the same construction. This checks the assessed construction, though their proof is different from the model's original argument.

Independent checking

Assessment of the initial proof and a separate complete human proof of the retained construction

Checker
Yangyang Cheng and Amedeo Sgueglia, authors
Scope
Theorem 1.3 pairwise-perfect matching construction
Basis
Reported by the linked checker
Evidence source

Human understanding Full

The authors explain the polygon-and-centre rotation construction, prime condition and how it proves Theorem 1.3.

Correction and publication history

2026-10-18 · publication

Gives an asymptotically complete pairwise-perfect collection for every large even order.

Read this published revision