Ternary-partition numerator at minus one

For a partition λ of n, its subsum polynomial is sp(λ,x)=∏ᵢ(1+x^λᵢ). Sum 1/sp over the specified partition family, combine over the denominator ∏ⱼ(1+xʲ)^⌊n/j⌋ for allowed parts j, then cancel the greatest common factor of the individual numerator summands.

For ternary partitions, whose parts are powers of three, is num_T(n,−1)=3^v₃(n!) for every n≥1, where v₃ is the exponent of 3?

Why it matters and what counts as progress

Why it matters: The evaluation predicts an exact prime-power value from the arithmetic of the factorial.

What counts as progress: A proof of the special-value formula for every n, including the initial cases, or a rigorously evaluated exception.

How the problem developed

  1. 11 May 2026 · Conjecture [1]

    Cristina Ballantine, George Beck, Brooke Feigon, and Kathrin Maurischat Introduced reciprocal subsum polynomials and posed special-value conjectures for the associated numerator polynomials, including the ternary case.

  2. 20 May 2026 · Special value [2]

    Evan Chen, Ken Ono, and Jujian Zhang, with AxiomProver-generated Lean proofs Proved the ternary special-value conjecture at x=−1 as part of six formalized coprimality, divisibility, special-value, and recurrence results.

AI contribution

Reciprocals of Partition Polynomials

Evan Chen, Ken Ono, Jujian Zhang

AxiomProver generated Lean proofs of Ballantine–Beck–Feigon–Maurischat Conjectures 2, 5, 7, 8, 9 and the intended corrected reading of 10, covering coprimality, divisibility, special values and a recurrence. It also found an n=4 counterexample to a printed binary log-concavity claim.

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Sources

  1. Ballantine, Beck, Feigon, and Maurischat, Reciprocals of Subsum Polynomials
  2. Chen, Ono, and Zhang, Reciprocals of Partition Polynomials
  3. Chen, Ono and Zhang, Reciprocals of Partition Polynomials
  4. AxiomMath, PartitionPolynomial formal proofs and comparators
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