Faces of root polytopes in all dimensions

Acta Crystallogr A Found Adv. 2016 Jul 1;72(Pt 4):465-71. doi: 10.1107/S2053273316004551. Epub 2016 May 13.

Abstract

In this paper the root polytopes of all finite reflection groups W with a connected Coxeter-Dynkin diagram in {\bb R}^n are identified, their faces of dimensions 0 ≤ d ≤ n - 1 are counted, and the construction of representatives of the appropriate W-conjugacy class is described. The method consists of recursive decoration of the appropriate Coxeter-Dynkin diagram [Champagne et al. (1995). Can. J. Phys. 73, 566-584]. Each recursion step provides the essentials of faces of a specific dimension and specific symmetry. The results can be applied to crystals of any dimension and any symmetry.

Keywords: Lie algebra; Lie groups; finite Coxeter groups; root polytopes.