The des-Wilf equivalence for two sets of West-2-stack-sortable patterns

About 9 years old · traced to

For a permutation pattern τ\tau, let Fndes⁡(τ;q)F_n^{\operatorname{des}}(\tau;q) denote the descent generating polynomial over permutations in Av⁡n(τ)\operatorname{Av}_n(\tau), and for sets of patterns let Fndes⁡(Π;q)F_n^{\operatorname{des}}(\Pi;q) be defined analogously. Write τ≡des⁡ρ\tau\equiv_{\operatorname{des}}\rho for equality of these polynomials for every nn. The des-Wilf equivalence conjecture. The two sets of patterns satisfy

{2341, 3241}≡des⁡{2413, 3142}.\{2341,\,3241\}\equiv_{\operatorname{des}}\{2413,\,3142\}.

The patterns in the left-hand set are the basis for the permutations that are West-22-stack-sortable, and the conjecture extends the paper's study of descent generating functions for avoidance classes. It is supported by the data considered in the paper, while no closed forms for the relevant functions are known.

References

Primary source

Caden Bielawa, Robert Davis, Daniel Greeson and Qinhan Zhou, “Descents and des-Wilf Equivalence of Permutations Avoiding Certain Non-Classical Patterns”, arXiv:1706.06231 (2018).

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.