Cycles of length divisible by five in graphs of minimum degree five - The k=5 case of Dean's conjecture

Elias Botsford

Botsford’s revised theorem says every finite simple graph with minimum degree at least five has a simple cycle whose length is divisible by five. The proof reduces a minimal counterexample to 5-weak graphs and treats bipartite, triangular and triangle-free cases.

Sources for this record

What was already known

Dean conjectured the corresponding divisible-cycle result for minimum degree at least k. Cases k=3,4 and all k≥6 were known; k=5 remained.

AI involvement AI-led

Elias Botsford authored and revised the proof. The paper credits generative AI, chiefly GPT-5.6 Sol, with the main results and also names Claude Opus 5, GLM 5.3 Flash and Danus; individual proof steps are not separately attributed.

The author explicitly attributes the main results primarily to generative AI; the exact roles of the listed systems and human repair are not separated.

Importance Major

If the full structural argument holds, the result closes the last case of Dean’s conjecture.

Limitations

Exact programs certify nine finite configuration propositions. They do not check the graph-to-state reductions or a revised exceptional-leaf step, and no complete human proof review is documented.

Technical verification Partial

The archived v1.0.1 programs and certificates check nine finite propositions; the graph-to-state reductions, exceptional-leaf repair and remaining structural proof are mathematical arguments in the paper without a documented complete human or formal check.

Independent checking

exhaustive enumeration, independent object detection for some cases, witness and certificate checking

Checker
Botsford’s archived finite verifiers
Scope
nine stated finite configuration propositions in bipartite and triangle-free branches
Basis
Reported by the linked checker
Evidence source

Human understanding Few

Default for missing documented human explanation: the author presents a structural proof and repair, but the record does not establish a human account of the central mechanism independent of the primarily AI-generated results.

Correction and publication history