Vincent Dumoncel: Isoperimetric profiles and quantitative orbit equivalence for lampshufflers

mardi 9 juin 2026, 11:15 → 12:15 Europe/Paris

Salle 112

Lampshufflers are semi-direct products having a geometry close to the one of lamplighters. in geometric group theory, they are also a source of examples of groups with unexpected and exotic behaviours. I will present a joint work with Corentin Correia, in which we study these groups from an analytical, geometric and measured point of view. In particular, we show a stability property for the existence of orbit equivalence couplings between lampshufflers, and by computing precisely their isoperimetric profiles, extending previous results from Erschler-Zheng and Saloff-Coste-Zheng, we show that our couplings are quantitatively optimal.