English

A combinatorial $\mathfrak{sl}_2$-action and the Sperner property for the weak order

Combinatorics 2020-01-06 v2 Representation Theory

Abstract

We construct a simple combinatorially-defined representation of sl2\mathfrak{sl}_2 which respects the order structure of the weak order on the symmetric group. This is used to resolve a conjecture of Stanley that the weak order has the strong Sperner property, and is therefore a Peck poset.

Keywords

Cite

@article{arxiv.1811.05501,
  title  = {A combinatorial $\mathfrak{sl}_2$-action and the Sperner property for the weak order},
  author = {Christian Gaetz and Yibo Gao},
  journal= {arXiv preprint arXiv:1811.05501},
  year   = {2020}
}

Comments

6 pages; v2: added conjecture and updated references

R2 v1 2026-06-23T05:14:30.323Z