2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/135817We construct a group K_n with properties similar to infinite Coxeter groups. In particular, it has a geometric representation featuring hyperplanes and simplicial chambers. The generators of K_n are given by 2-element subsets of {0, .., n}. We give some easy combinatorial results on the finite residues of K_n.21 pages, 6 figuresCombinatorics52B30 (primary), 20F55, 22E40 (secondary)text