An Explicit Counterexample to Stanley's Rankwise Lower-Bound Conjecture for Differential Posets

Xinan Dai, Wenhao Deng, Yingdong Shi, Tailin Wu, Yuchen Yang

For each integer r≥3, Dai and coauthors construct an infinite r-differential poset that agrees with Yʳ through rank three but has rank-four size |(Yʳ)₄|−⌊r/3⌋. At r=3 the first sizes are 1, 3, 9, 22, 50, compared with 51 for Y³.

Sources for this record

What was already known

Stanley proposed a coefficientwise lower bound by Yʳ. Earlier rank-growth and rank-gap theorems did not imply that proposed comparison.

AI involvement AI-autonomous

The paper says TARS autonomously generated the counterexample. Xinan Dai, Wenhao Deng, Yingdong Shi, Tailin Wu and Yuchen Yang examined and independently verified it.

The source explicitly says the TARS agent system autonomously generated the retained counterexample before human examination.

Importance Notable

Refutes Stanley’s rankwise lower-bound proposal for every r≥3.

Limitations

The result leaves r=1 and r=2 open. The authors report independent examination and verification of the construction; no separate checking report or TARS search transcript is supplied.

Technical verification Formal (human)

The named human authors report independent verification of the counterexample, and the paper gives the finite incidence replacement and infinite reflection extension. No machine proof check is documented. The reported completed human review supports Formal, without claiming independent reproduction here.

Independent checking

Independent human examination and verification of the TARS construction

Checker
Xinan Dai, Wenhao Deng, Yingdong Shi, Tailin Wu and Yuchen Yang, human authors
Scope
The rank-four counterexample and its extension to infinite r-differential posets for r≥3
Basis
Reported by the linked checker
Evidence source

Human understanding Full

The human authors examined the construction and present its point-and-pair incidence invariant, explicit block replacement and reflection extension, explaining the mechanism of the assessed rank-four failure.

Correction and publication history