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Topics in Geometric Group Theory |
| November 05, 2007 to November 09, 2007 |
| Organized By: Noel Brady, Mike Davis, Mark Feighn |
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| Parent Programs: |
| Geometric Group Theory |
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| Return to Workshop Description |
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Rank-1 isometries on CAT(0) spaces and quasi-homomorphisms
Tuesday November 6, 2007
03:30PM - 04:20PM
Speakers:
Koji Fujiwara
Abstract:
Generalizing a construction of quasi-homomorphisms on a group
acting on hyperbolic spaces, we construct quasi-homomorphisms
on a group acting on a CAT(0)-space with rank-1 isometries.
As an application, we characterize finite volume, locally symmetric spaces
of rank at least two among finite volume complete Riemannian manifolds
of non-positive
curvature using quasi-homomorphisms on the fundamental groups.
The construction also applies to the action of a mapping class group
on the Teichmuller space with Weil-Petersson metric.
We show pseudo-Anosov elements are rank-1 in our sense.
This is a joint work with Bestvina.
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