Non-perturbative analysis of the gravitational energy in Ho\v{r}ava   Theory
  We perform a non-perturbative analysis of the constraints of the Ho\v{r}ava Gravitational theory. In distinction to Einstein gravity the theory has constraints of the first class together with second class ones. We analyze the consequences of having to impose second classes constraints at any time in the quantum formulation of the theory. The second class constraints are formulated as strongly elliptic partial differential equations allowing a global analysis on the existence and uniqueness of the solution. We discuss the possibility of formulating the theory in terms of a master action with first class constraints only. In this case the Ho\v{r}ava theory would correspond to a gauged fixed version of the master theory. Finally we obtain, using the non-perturbative solution of the constraints, the explicit expression of the gravitational energy. It is, under some assumptions, always positive and the solution of Ho\v{r}ava field equations at minimal energy is the Minkowski metric. 
Jorge Bellor\'in, Alvaro Restuccia, Adri\'an Sotomayor
hep-th