Carə tuttə,
Vi ricordo che domani 4 Maggio alle 11 in Aula Seminari si terrà il seminario di Claudio Llosa Isenrich (Karlsruhe Institute of Technology) dal titolo "Finiteness properties, subgroups of hyperbolic groups and complex hyperbolic lattices". Di seguito l'abstract.
Hyperbolic groups form an important class of finitely generated groups that has attracted much attention in Geometric Group Theory. We call a group of finiteness type $F_n$ if it has a classifying space with finitely man cells of dimension at most $n$, generalising finite presentability, which is equivalent to type $F_2$. Hyperbolic groups are of type $F_n$ for all $n$ and it is natural to ask if their subgroups inherit these strong finiteness properties. We use methods from complex geometry to show that every uniform arithmetic lattice with positive first Betti number in $PU(n,1)$ admits a finite index subgroup, which maps onto the integers with kernel of type $F_{n−1}$ and not $F_n$. This answers an old question of Brady and produces many finitely presented non-hyperbolic subgroups of hyperbolic groups. This is joint work with Pierre Py.
Ricordiamo che le informazioni sui prossimi seminari si trovano sul sito<https://www.dm.unipi.it/categoria-evento/geometry-seminar/>. La settimana prossima avremo due seminari, entrambi Giovedì 11 Maggio in Aula Seminari: alle 10 avremo Alejandro Gil-García (Universität Hamburg) che ci parlerà di "A class of locally inhomogeneous complete quaternionic Kähler manifolds", mentre alle 11.30 avremo R. Inanç Baykur (University of Massachusetts Amherst) che ci parlerà di "Exotic 4-manifolds with signature zero".
Vi aspettiamo!
Buona giornata,
Alice, Filippo e Giuseppe
