Target Space Dualities of Heterotic Grand Unified Theories

In this article we summarize and extend the ideas and investigations on so called target space dualities of heterotic models with (0,2) worldsheet supersymmetry as they were partly presented on the String-Math 2011 conference. After the generic description of the duality, we give some novel examples involving vector bundles that are not deformations of the tangent bundle but more generic ones corresponding to SO(10) and SU(5) gauge theories in four dimensions. We show explicitly that the necessary conditions for a duality also hold for compactifications of this kind. Finally we will present the results of the large landscape scan of E_6 models.