T-duality, Non-geometry and Lie Algebroids in Heterotic Double Field   Theory
  A number of issues in heterotic double field theory are studied. This includes the analysis of the T-dual configurations of a flat constant gauge flux background, which turn out to be non-geometric. Performing a field redefinition to a non-geometric frame, these T-duals take a very simple form reminiscent of the constant Q- and R-flux backgrounds. In addition, it is shown how the analysis of arXiv:1304.2784 generalizes to heterotic generalized geometry. For every field redefinition specified by an O(D,D+n) transformation, the structure of the resulting supergravity action is governed by the differential geometry of a corresponding Lie algebroid. 
Ralph Blumenhagen, Rui Sun
hep-th math-ph math.MP