Plane 5D worlds and simple compactification
  We obtain a new kind of exact solution to vaccum Einstein field equations that contain both Minkowsian world and a special 5D curved spacetime with particularly free structure. This special world is defined by an arbitrary function and a space of three parameters. We suggest that this solution could correct (in principle) certain aspects of the physics in flat spacetime. 
David Solano and Rodrigo Alvarado