English

Reduced word enumeration, complexity, and randomization

Combinatorics 2022-06-08 v2

Abstract

A reduced word of a permutation ww is a minimal length expression of ww as a product of simple transpositions. We examine the computational complexity, formulas and (randomized) algorithms for their enumeration. In particular, we prove that the Edelman-Greene statistic, defined by S. Billey-B. Pawlowski, is typically exponentially large. This implies a result of B. Pawlowski, that it has exponentially growing expectation. Our result is established by a formal run-time analysis of A. Lascoux-M.-P. Sch\"utzenberger's transition algorithm. The more general problem of Hecke word enumeration, and its closely related question of counting set-valued standard Young tableaux, is also investigated. The latter enumeration problem is further motivated by work on Brill-Noether varieties due to M. Chan-N. Pflueger and D. Anderson-L. Chen-N. Tarasca.

Keywords

Cite

@article{arxiv.1901.03247,
  title  = {Reduced word enumeration, complexity, and randomization},
  author = {Cara Monical and Benjamin Pankow and Alexander Yong},
  journal= {arXiv preprint arXiv:1901.03247},
  year   = {2022}
}

Comments

23 pages. v2: added reference to University of Washington PhD thesis of B. Pawlowski, which proves a stronger version of Theorem 1.1

R2 v1 2026-06-23T07:08:15.603Z