 The definition of nonseparability becomes problematic in general relativity, since its application requires that one identify the same region R in possible spacetimes with different geometries. But while there is no generally applicable algorithm for making a uniquely appropriate identification, some identification may appear salient in a particular case. For example, one can meaningfully discuss whether or not the field is the same everywhere in the region outside the solenoid in the  Aharonov-Bohm effect  with an increased current flowing, even though the size of the current will have a (tiny) influence on the geometry of that region. Note that the definition of nonseparability does not require that one identify the same point in spacetimes of distinct geometries.