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.
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