Stable quotients and the holomorphic anomaly equation

An example of such a twisted theory is the formal quintic defined by a hyperplane section of P4 in all genera via the Euler class of a complex. The formal quintic theory is found to satisfy the holomorphic anomaly equations conjectured for the true quintic theory. Therefore, the formal quintic theory and the true quintic theory should be related by transformations which respect the holomorphic anomaly equations.