Three proofs from dynamics of rigidity of surface group actions
Presenter
April 15, 2015
Keywords:
- surface group
- rigidity results
- discrete subgroups
- folations, leaves
- Hitchin representation
- geometric actions
MSC:
- 37D20
- 37Dxx
- 37-xx
- 30F60
- 30Fxx
- 53D18
- 53C24
- 53Cxx
- 53C12
- 53-xx
Abstract
In previous talks (not a prerequisite!), I've described examples of actions of a surface group G on the circle that are totally rigid -- they are essentially isolated points in the representation space Hom(G, Homeo+(S^1))/~. These examples are interesting from many perspectives, ranging from foliation theory to the classification of connected components of representation spaces.
In this talk, I will illustrate three separate approaches to prove rigidity of these actions, including my original proof. Each one uses fundamentally different techniques, but all have a common dynamical flavor:
1. Structural stability of Anosov foliations (Ghys/Bowden, under extra hypotheses)
2. Rotation number "trace coordinates" on the representation space (Mann)
3. New "ping-pong" lemmas for surface groups (Matsumoto)