“…In particular, there are many different non-relativistic gravity theories that are based on the extensions of the Bargmann algebra that cannot be accessed from the Poincaré algebra by means of an Inonu-Wigner contraction. A wellknown example of this kind, called the three-dimensional extended Bargmann gravity [1], has been studied from various angles including its supersymmetric completion and matter couplings [2], its cosmological and non-relativistic conformal [3] and Maxwellian [4] extensions as well as the construction of its parity-odd cousin, the exotic extended Bargmann supergravity [5]. Another important example that goes beyond the Bargmann symmetries, which was put forward in [6,7], is based on the argument that although the Bargmann symmetries are sufficient to establish the Poisson's equation for Newtonian gravity in a covariant manner, an action principle for Newtonian gravity requires extended symmetries beyond the standard Bargmann symmetries.…”