On the question of symmetries in non-relativistic diffeomorphism   invariant theories
  A novel algorithm is provided to couple a Galilean invariant model with curved spatial background by taking nonrelativistic limit of a unique minimally coupled relativistic theory, which ensures Galilean symmetry in the flat limit and canonical transformation of the original fields. That the twin requirements are fulfilled is ensured by a new field, the existence of which was demonstrated recently from Galilean gauge theory. The ambiguities and anomalies concerning the recovery of Galilean symmetry in the flat limit of spatial non relativistic diffeomorphic theories, reported in the literature, are focused and resolved from a new angle. 
Rabin Banerjee, Sunandan Gangopadhyay, Pradip Mukherjee
hep-th gr-qc