Landscape Study of Target Space Duality of (0,2) Heterotic String Models
  In the framework of (0,2) gauged linear sigma models, we systematically generate sets of perturbatively dual heterotic string compactifications. This target space duality is first derived in non-geometric phases and then translated to the level of GLSMs and its geometric phases. In a landscape analysis, we compare the massless chiral spectra and the dimensions of the moduli spaces. Our study includes geometries given by complete intersections of hypersurfaces in toric varieties equipped with SU(n) vector bundles defined via the monad construction. 
Ralph Blumenhagen and Thorsten Rahn
hep-th math.AG