Any origin is never an infinitesimal point, but a sphere of small radius 
that forms a basis for measurement.  When the radius is small, the sphere 
approximates an infinitesimal point, and measurements from either the inner 
or outer surface of the sphere are the same.  For a sphere of large radius, 
events are measured from either the inner or outer surface of the sphere, as 
well.  Consequently, inverted space is the same reality as noninverted 
space, as I demonstrate with the mathematics at my web page,

http://mypeoplepc.com/members/jon8338/math/id18.html