The topology on the space of left orderings of a group
  Let G be a group and let O_G denote the set of left orderings on G. Then O_G can be topologized in a natural way, and we shall study this topology to answer three conjectures. In particular we shall show that O_G can never be countably infinite. Furthermore in the case G is a countable nonabelian free group, we shall show that O_G is homeomorphic to the Cantor set and that the positive cone of a left order on G is not finitely generated. Generalizations to locally indicable groups will also be considered. 
Peter A. Linnell