  We explain the homological relation between the Frobenius structure on the
deformation space of Calabi-Yau manifold and the gauge theory of
Kodaira-Spencer gravity. We show that the genus zero generating function of
descendant invariants on Calabi-Yau manifolds from Barannikov's semi-infinite
variation of Hodge structures is equivalent to the Kodaira-Spencer gauge theory
at tree level.
