Seminario Teoría de Grupos
On an uncountable family of simple Kazhdan groups in dimension 16
Ponente: Roman Sauer (Karlsruhe Institute of Technology)Fecha: jueves 07 de mayo de 2026 - 11:30Lugar: Aula Naranja, ICMAT
Resumen:
We construct a family of simple Kazhdan groups that have rational cohomological dimension 16 and uncountably many values of second l2-Betti numbers. Along the way, we present new constructions of measurably diverse finitely generated groups, and we prove that the second l2-Betti number is far from being semi-continuous in the space of marked groups.
The construction relies on three ingredients:
- the theory of group-theoretic Dehn fillings,
- the Cohen-Lyndon property and its excision principle
- higher property T
This is joint work with Francesco Fournier-Facio.
