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First page of Reciprocals of Partition Polynomials

Reciprocals of Partition Polynomials

Evan Chen, Ken Ono, Jujian Zhang

math.CO May 20, 2026 · v1
AxiomProver produced Lean/mathlib formalizations of six partition-polynomial conjectures.
Ballantine--Beck--Feigon--Maurischat introduced the subsum polynomial \[ \operatorname{sp}(λ,x):=\prod_i (1+x^{λ_i}) \] attached to an integer partition $λ$, and studied rational functions obtained by summing reciprocals of these polynomials over natural classes of partitions. They posed ten conjectures which naturally divide into coprimality and divisibility questions, special-value and recurrence formulas, and coefficient-shape problems. We prove all of the conjectures in the first two families: the ordinary and binary coprimality/divisibility conjectures, and the odd and ternary special-value/recurrence conjectures. AxiomProver autonomously produced Lean/mathlib formalizations and machine-checkable proofs of these six conjectures, and also discovered a counterexample to the statement as printed; the corrected form remains open.

Ballantine, Beck, Feigon, and Maurischat introduced subsum polynomials attached to integer partitions and posed ten conjectures about rational functions formed by summing reciprocals of these polynomials over natural classes of partitions. The conjectures concern coprimality/divisibility and special-value/recurrence properties.

The authors prove six of the ten conjectures spanning two families: the ordinary and binary coprimality/divisibility conjectures, and the odd and ternary special-value/recurrence conjectures. The proofs use cyclotomic polynomial techniques, analyzing which roots of unity annihilate the reduced numerator polynomial by tracking how cyclotomic factors distribute across partition summands. AxiomProver autonomously produced Lean/mathlib formalizations and machine-checkable proofs of these six conjectures, and also discovered a counterexample to one conjecture as printed.

All six conjectures in the coprimality/divisibility and special-value/recurrence families are proved. A counterexample to one conjecture as originally stated was found by the automated prover; the corrected form remains open.