Type IIB theory on half-flat manifolds

In this paper we derive the low-energy effective action of type IIB theory compactified on half-flat manifolds and show that this precisely coincides with the lowenergy effective action of type IIA theory compactified on a Calabi-Yau manifold in the presence of NS three-form fluxes. In this way we provide a further check of the recently formulated conjecture that half-flat manifolds appear as mirror partners of Calabi-Yau manifolds when NS fluxes are turned on.