Geometric Structures on 3-manifolds

Sageev associated to a codimension 1 subgroup $H$ of a group $G$ a cube complex on which $G$ acts by isometries, and proved this cube complex is always CAT(0). Haglund and Wise developed a theory of special cube complexes, whose fundamental groups have many favorable properties. In this talk, the basics of this theory will be described, along with applications.