Seminario Teoría de Grupos
Normalizers of parabolic subgroups in Artin and Coxeter groups
Ponente: Owen Garnier (Universidad de Sevilla)Fecha: miércoles 05 de noviembre de 2025 - 16:30Lugar: Aula Gris 3, ICMAT
Resumen:
Parabolic subgroups are important subgroups defined in Coxeter groups and their associated Artin groups. In both settings, the normalizer of a parabolic subgroup decomposes as a semidirect product which is understood combinatorially by introducing a suitable groupoid. For Coxeter groups, this groupoid is the Brink-Howlett groupoid, for Artin groups it is the ribbon groupoids.
This talk will start by presenting these "classical" groupoids. I will then present a joint work with E. Heng, A. Licata and O. Yacobi, in which we provide a geometric interpretation of these groupoids using the so-called Tits cone intersection attached to a parabolic subgroup.
