Combinatorics of affine cactus groups

Abstract

This article deals with the study of affine cactus groups from a combinatorial point of view. Those groups are extensions of cactus groups, which are related to braid and diagram groups and have gained an important place in many mathematics topics. We first show that affine cactus groups may be described as cactus groups on Coxeter groups of type eAn. Then, we prove that these groups embed into a semi-direct product of Coxeter groups, which allows us to obtain a number of combinatorial properties of affine cactus groups, such as the solubility of the world problem or the fact that their centre is trivial.