Student Geometry and Topology Archives for Fall 2013 to Spring 2014
Discrete groups of isometries: dynamical invariants
When: Tue, September 18, 2012 - 3:30pmWhere: Math 1313
Speaker: Andrew Sanders (UMD) -
Introduction to Parabolic Geometries
When: Tue, October 2, 2012 - 3:30pmWhere: Math 1313
Speaker: Katharina Neusser (Australian National University) - http://maths.anu.edu.au/~neusser/
For a Lie group G and a closed subgroup H a Cartan geometry of type (G,H) can be viewed (in a sense) as a curved analog of the homogeneous space G/H.
Parabolic geometries are Cartan geometries, whose homogeneous model is a homogeneous space of a semisimple Lie group by a parabolic subgroup.
It turns out that many interesting geometric structures can be described as parabolic geometries and so parabolic geometries offer a uniform approach to a broad variety of geometric structures. Among these structures we have conformal structures, projective structures, partially integrable almost CR structures of hypersurface type and certain types of generic distributions. In my talk I will give an introduction to parabolic geometries and an overview of some of the tools that were developed in the last decades to study them.
Patterson-Sullivan measures for convex, cocompact Kleinian groups
When: Tue, November 6, 2012 - 3:30amWhere: Math 1313
Speaker: Andrew Sanders (UMCP) - www.math.umd.edu/~andysan
Abstract: Continuing with our series of talks about Patterson-Sullivan theory, we will study special properties of Patterson-Sullivan measures in the case that the group is convex co-compact. In particular, we will show that the Patterson-Sullivan measure is a multiple of the Hausdorff measure in dimension equal to the critical exponent of the group. If time permits, we will also discuss the ergodicity properties of this measure.