Wednesday, 11 April 2018
Nils Amend: Restrictions of Arrangements and Asphericity
In recent years, Bessis completed the proof that every reflection arrangement admits an aspherical complement. We prove that the same ist true for the restrictions of the infinite families of reflection arrangements. In addition, we discuss a certain class of subarrangements of Coxeter arrangements, the arrangements of ideal type, which yield two (real) families of aspherical arrangements that admit restrictions which are not aspherical. These seem to be the first known instances of this phenomenon.This is joint work with Tilman Möller and Gerhard Röhrle.