A network-found tree counters Collins's peak conjecture

Wagner's deep cross-entropy search found a 48-vertex tree with normalized peak positions p_A(T)/m(T)=1/7 and p_D(T)/n(T)=1/2 for the adjacency and distance characteristic polynomials. The unequal peak positions refute the peak-alignment part of Collins's conjecture.

Sources for this record

What was already known

Kathleen Collins conjectured that, for any tree, the nonzero adjacency-polynomial coefficient sequence is unimodal and peaks at the same normalized location as the distance-polynomial coefficient sequence (1989, as quoted in Wagner, Conjecture 2.4). Wagner's paper describes earlier algorithmic searches for extremal combinatorial structures, including his 2020 linear-programming method; this specific 48-vertex tree is presented as a new counterexample.

AI involvement AI-centered

Wagner selected the conjecture and reward function and designed the deep cross-entropy search. The network generated the retained 48-vertex tree; Wagner then interpreted its structure and proved a broader infinite-family result by hand.

Wagner designed the deep cross-entropy search, selected the reward and interpreted the result; the network produced the retained 48-vertex tree.

Importance Modest

This gives a concrete counterexample to the peak-alignment part of a tree-polynomial conjecture. Wagner used its structure to derive a human-proved infinite family, which is distinct from the network's finite output.

Limitations

The curated AI contribution is the 48-vertex finite tree in Figure 7, not Wagner's later theorem on an infinite family. The paper reports the coefficient-peak calculations, but no separately documented rigorous check of the exact finite instance was located.

Technical verification Partial

The paper reports computed coefficient-peak positions 1/7 and 1/2 for the finite tree but gives no separately documented exact certificate or completed independent check. This is a source-reported finite calculation.

Human understanding Full

Wagner identifies the tree’s salient high-degree-vertex structure and uses it to derive and prove a broader family, showing human understanding of the finite counterexample’s mechanism.

Correction and publication history

2026-10-18 · publication

Primary-paper review of the network-produced finite counterexample; local inclusion without notification.

Read this published revision