Inhaltspezifische Aktionen

Finiteness properties of subgroups of hyperbolic groups

Claudio Llosa Isenrich (KIT)

Wann

11.05.2022 von 16:15 bis 17:45 (Europe/Berlin / UTC200)

Name des Kontakts

Telefon des Kontakts

32080

Termin zum Kalender hinzufügen

iCal

Hyperbolic groups form an important class of finitely presented groups. They are known to be of type Fn for all n, that is, they admit a classifying space with finitely many cells in all dimensions. It is natural to ask if subgroups of hyperbolic groups inherit these strong finiteness properties: For n ≥ 1, is there a subgroup of a hyperbolic group of type Fn, but not of type Fn+1? Brady raised this question in 1999, following his construction of examples for n=2, while the first examples for n=1 were constructed by Rips in 1982. Very recently Martelli, Py and myself constructed examples for n=3, while the question for n ≥ 4 remained open. In this talk I will explain how one can apply methods from complex geometry to uniform arithmetic lattices in SU(n,1) to answer Brady's question for all n. This is joint work with Py.