I am engaged in topology, geometry, and algebra---especially in geometric group theory. My main objects of interest include buildings and other CAT(0) spaces, arithmetic groups and their relatives such as groups of (outer) automorphisms of free groups or mapping class groups of surfaces, Thompson's groups, and other important groups and spaces.
I mainly study (homological) finiteness properties of groups and related invariants. The main tool is to consider actions of these groups on associated spaces.
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