English

On inversion sets and the weak order in Coxeter groups

Group Theory 2016-05-10 v3 Combinatorics

Abstract

In this article, we investigate the existence of joins in the weak order of an infinite Coxeter group W. We give a geometric characterization of the existence of a join for a subset X in W in terms of the inversion sets of its elements and their position relative to the imaginary cone. Finally, we discuss inversion sets of infinite reduced words and the notions of biconvex and biclosed sets of positive roots.

Keywords

Cite

@article{arxiv.1502.06926,
  title  = {On inversion sets and the weak order in Coxeter groups},
  author = {Christophe Hohlweg and Jean-Philippe Labbé},
  journal= {arXiv preprint arXiv:1502.06926},
  year   = {2016}
}

Comments

22 pages; 10 figures; v2 some references were added; v2: final version, to appear in European Journal of Combinatorics

R2 v1 2026-06-22T08:36:55.953Z