Intersection of Parabolic Subgroups in Euclidean Braid Groups: a short proof

Abstract

We give a short proof for the fact, already proven by Thomas Haettel, that the arbitrary intersection of parabolic subgroups in Euclidean Braid groups $A[{\tilde{A}}_n]$ is again a parabolic subgroup. To that end, we use that the spherical-type Artin group $A[B_{n+1}]$ is isomorphic to $A[{\tilde{A}}_n]⋊\mathbb{Z}$.

3 pages, 2 figures