Normalisers of parabolic subgroups of Artin--Tits groups and Tits cone intersections

Owen Garnier, Edmund Heng, Anthony Licata +1

Let $\Gamma$ be a Coxeter diagram and let $J\subseteq \Gamma$. Motivated by 3-fold flops, Iyama and Wemyss study the hyperplane arrangement in the Tits cone intersection of $J$, which is a…