On the Existence of Stable bundles with prescribed Chern classes on   Calabi-Yau threefolds
  We prove a case of the conjecture of Douglas, Reinbacher and Yau about the existence of stable vector bundles with prescribed Chern classes on a Calabi-Yau threefold. For this purpose we prove the existence of certain stable vector bundle extensions over elliptically fibered Calabi-Yau threefolds. 
Bjorn Andreas, Gottfried Curio
math.AG hep-th math.DG