Group actions on dendrites and curves
  We establish obstructions for groups to act by homeomorphisms on dendrites. For instance, lattices in higher rank simple Lie groups will always fix a point or a pair. The same holds for irreducible lattices in products of connected groups. Further results include a Tits alternative and a description of the topological dynamics.   We briefly discuss to what extent our results hold for more general topological curves. 
Bruno Duchesne and Nicolas Monod
math.DS math.GR