Bijection between constrained Delannoy paths and Catalan paths avoiding symmetric peaks

For a positive integer nn, let EPn,n(1)(NE,EN)E\mathcal{P}^{(1)}_{n,n}(NE,EN) be the set of Delannoy paths from (0,0)(0,0) to (n,n)(n,n) consisting of north-steps N=(0,1)N=(0,1), east-steps E=(1,0)E=(1,0), and diagonal-steps D=(1,1)D=(1,1) that avoid the patterns NENE and ENEN, end with an east step EE, and are not below y=xy=x. Let the second set consist of Catalan paths of size n+1n+1 avoiding symmetric peaks, where a symmetric peak is a peak whose maximal mountain has the form NiEiN^iE^i.

Delannoy–Catalan bijection conjecture. For every positive integer nn, there exists a bijection between EPn,n(1)(NE,EN)E\mathcal{P}^{(1)}_{n,n}(NE,EN) and the set of Catalan paths of size n+1n+1 avoiding symmetric peaks.

This conjecture proposes a direct combinatorial correspondence between a class of constrained Delannoy paths and Catalan paths with a local peak-avoidance condition. The surrounding discussion identifies the related generating-function identity, but the supplied text gives no evidence that this bijection has been proved or disproved.

Sources & referencesView supporting material

Primary source

Seunghyun Seo and Heesung Shin, “On Delannoy paths without peaks and valleys”, arXiv:2203.07770 (2022).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.