Small unordered Davenport constant of the order-125 Heisenberg group
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For the exponent-five Heisenberg group of order 125, determine the small unordered Davenport constant: the greatest length of a sequence with no nonempty subsequence whose terms can be ordered to multiply to the identity. The target value is twelve, requiring a length-twelve example and an upper bound for every thirteen-term sequence.
Why it matters and what counts as progress
Why it matters: It determines the first stated open prime case of the Heisenberg small Davenport-constant prediction, with sequence order treated as unrestricted.
What counts as progress: Match a product-one-free construction with an upper bound for all thirteen-term sequences; the unordered subsequence invariant is the target.
How the problem developed
- 4 Nov 2023 · Special case [1]
Naveen K. Godara and Siddhartha Sarkar Proved that the small Davenport constant of the exponent-3 non-abelian group of order 27 is 6, providing the lower-prime case in this Heisenberg-group line of work.
- 15 Jul 2026 · Exact result [2]
Patrick White Proved d(H_125)=12; the upper bound reduces to a finite spread bound checked by exhaustive C and Python searches, with auxiliary lemmas machine-checked.
AI contribution
The small Davenport constant of the Heisenberg group of order 125
For the exponent-five Heisenberg group of order 125, the small unordered Davenport constant is twelve: x⁴y⁴v⁴ is product-one-free, and every thirteen-term sequence has a product-one subsequence in some ordering.
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AI-led work reports small Davenport constant twelve for H₁₂₅