Form field theory on Calabi-Yau threefold
  We show how the natural Abelian duality of 2 and 3-form gravity theories on seven dimensional manifold CY3xS1, leads to an S-duality between 2 and 3-form theories on simply connected CY3. The massless sector of the 2-form field theory on CY3 corresponds to the A model string field theory. We discuss the complex structure independence of the 2-form theory for a general Kahler manifold and derive the holomorphic anomaly equations for simply connected CY3. 
Farhang Loran, Hesam Soltanpanahi