Study of the OSV Conjecture for 4D N=2 Extremal Black Holes in Type IIB   String Theory
  In this survey we study the OSV conjecture for 4D N=2 extremal black holes of type IIB suprstring theory. We apply T-duality to find the generalized prepotential of the low energy limit of this superstring theory up to one-loop order in the closed string coupling. On the other hand, we calculate the tree-level and one-loop free energies of B-model topological string theory. To compare them we will explicitly show that the OSV conjecture holds for type IIB N=2 extremal black holes. 
Farzad Omidi
hep-th