Past Junior Topology and Group Theory Seminar

9 February 2011
16:00
Alessandro Sisto
Abstract
After a quick-and-dirty introduction to nonstandard analysis, we will define the asymptotic cones of a metric space and we will play around with nonstandard tools to show some results about them. For example, we will hopefully prove that any separable asymptotic cone is proper and we will classify real trees appearing as asymptotic cones of groups.
  • Junior Topology and Group Theory Seminar
2 November 2010
16:00
Benno Kuckuck
Abstract
Geoghegan's stack construction is a tool for analysing groups that act on simply connected CW complexes, by providing a topological description in terms of cell stabilisers and the quotient complex, similar to what Bass-Serre theory does for group actions on trees. We will introduce this construction and see how it can be used to give results on finiteness properties of groups.
  • Junior Topology and Group Theory Seminar

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