5 papers
Spotted disk and sphere graphs I
Ursula Hamenstädt
The disk graph of a handlebody H of genus g at least 2 with m marked points on the boundary is the graph whose vertices are isotopy classes of disks disjoint from the marked points…
Signature of surface bundles and bounded cohomology
Ursula Hamenstädt
Extending a result of Morita, we show that all tautological classes of the moduli space of genus g curves are bounded. As an application, we obtain that for a surface bundle $E\to…
The Geometry of the Handlebody Groups II: Dehn functions
Ursula Hamenstädt, Sebastian Hensel
We show that the Dehn function of the handlebody group is exponential in any genus . On the other hand, we show that the handlebody group of genus is cubical, biautoma…
Dynamical properties of the Weil-Petersson metric
Ursula Hamenstadt
Let S be a non-exceptional oriented surface of finite type. We discuss the action of subgroups of the mapping class group of S on the CAT(0)-boundary of the completion of Teichmuel…
Isometry groups of proper hyperbolic spaces
Ursula Hamenstadt
Let X be a proper hyperbolic geodesic metric space and let G be a closed subgroup of the isometry group Iso(X) of X. We show that if G is not amenable then its second continuous bo…