Description
We analyze N=2 perturbative and non-perturbative corrections in type I orbifold models where a dual heterotic description is available. We consider in particular the Bianchi-Sagnotti-Gimon-Polchinski orbifold. By exploiting perturbative calculations of the physical gauge couplings on the heterotic side, we obtain multi-instanton and one-loop string corrections to the K\"ahler potential and the gauge kinetic
function. We argue that these corrections are universal in a given class of models where target-space
modular invariance holds.
Author
Emilian Dudas
(Ecole Polytechnique and U. Paris-Sud, Orsay)
