English

A characterization of simplicial oriented geometries as groupoids with root systems

Group Theory 2019-10-16 v1 Combinatorics

Abstract

This paper shows that simplicial oriented geometries can be characterized as groupoids with root systems having certain favorable properties, as conjectured by the first author. The proof first translates Handa's characterization of oriented matroids, as acycloids which remain acycloids under iterated elementary contractions, into the language of groupoids with root systems, then establishes favorable lattice theoretic properties of a generalization of a construction which Brink and Howlett used in their study of normalizers of parabolic subgroups of Coxeter groups and uses Bj\"orner-Edelman-Ziegler's lattice theoretic characterization of simplicial oriented geometries amongst oriented geometries.

Keywords

Cite

@article{arxiv.1910.06665,
  title  = {A characterization of simplicial oriented geometries as groupoids with root systems},
  author = {Matthew Dyer and Weijia Wang},
  journal= {arXiv preprint arXiv:1910.06665},
  year   = {2019}
}

Comments

39 pages

R2 v1 2026-06-23T11:44:01.979Z