Peter Ozsvath is a professor of mathematics at Princeton University. He started his mathematical career working on gage theory and Seiberg-Whitten equations. Later, together with Zoltan Szabo, he created the theory of Heegaard Floer Homology which is currently a major theme in the research in 3-manifold theory. Heegaard Floer Homology is an invariant of a closed 3-manifolds which is computed using a Heegaard diagram of the manifold. Later they expanded this theory to  a theory called Knot Floer Homology which applies to manifolds which are knot complements. A knot in a three-manifold induces a filtration on the Heegaard Floer homology groups, and the filtered homotopy type is a powerful invariant of the knot. In particular it categorifies the Alexander polynomial and can detect the genus of the knots. The Knot Floer Homology theory is playing now a central role in trying to determine which knots admit surgeries resulting in lens spaces. Both theories have settled some long standing conjectures in knot theory

Prof.  Ozsváth's homepage

http://math.mit.edu/~petero/