English

Rational Noncrossing Coxeter-Catalan Combinatorics

Combinatorics 2022-08-02 v1 Representation Theory

Abstract

We solve two open problems in Coxeter-Catalan combinatorics. First, we introduce a family of rational noncrossing objects for any finite Coxeter group, using the combinatorics of distinguished subwords. Second, we give a type-uniform proof that these noncrossing Catalan objects are counted by the rational Coxeter-Catalan number, using the character theory of the associated Hecke algebra and the properties of Lusztig's exotic Fourier transform. We solve the same problems for rational noncrossing parking objects.

Keywords

Cite

@article{arxiv.2208.00121,
  title  = {Rational Noncrossing Coxeter-Catalan Combinatorics},
  author = {Pavel Galashin and Thomas Lam and Minh-Tâm Quang Trinh and Nathan Williams},
  journal= {arXiv preprint arXiv:2208.00121},
  year   = {2022}
}

Comments

42 pages

R2 v1 2026-06-25T01:20:44.783Z