Hamilton decompositions of the directed 5-torus for odd modulus

SangHyun Park

For every odd m≥3, the directed Cayley graph of (Z/mZ)^5 with the five positive coordinate generators decomposes into five directed Hamilton cycles.

Sources for this record

What was already known

The directed three-torus was known. Older product results and surveys did not give this five-dimensional decomposition for all odd moduli.

AI involvement AI-centered

Park credits GPT-5.5 Pro with retained zero-set selector design and block-recurrence case analysis. Park designed and completed the construction, checked the paper and Lean theorems, and explained the return-map proof.

The author identifies model-origin selector design and recurrence case analysis as retained central pieces of the five-torus construction.

Importance Notable

Extends the return-map construction to a new infinite five-dimensional family.

Limitations

Even moduli and higher dimensions remain outside the theorem. The reported Lean theorem covers every odd m≥3 with finite certificate branches, alongside Park’s stated human check.

Technical verification Formal (Lean 4 with exact finite certificate branches + human)

Park reports a Lean 4 theorem for the same directed Cayley-edge statement for every odd m≥3, with finite certificate branches, and explicitly reports human verification of all mathematical content. Appendix C identifies the theorem, commit and build command. Neither check was reproduced here.

Independent checking

Author verification of all mathematical content and formal theorems, expressly stated in the AI disclosure

Checker
Sanghyun Park
Scope
The paper's complete odd-modulus directed five-torus construction and Lean theorems
Basis
Reported by the linked checker
Evidence source

Formal checking

Top-level D5Odd.D5_odd_cayley_unconditional and lake build D5Odd at the cited commit

Checker
Lean 4 type checker on Park's D5Odd development
Scope
Hamilton decomposition of Cay((Z/mZ)^5,{e0,…,e4}) for every odd m≥3 and finite m=3/matching branches
Basis
Reported by the linked checker
Evidence source

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

Human understanding Full

Park explains the Latin-table selector, layer matching, normalized return map and block recurrence that produce a single cycle in each colour.

Correction and publication history