As for relativism, why not use relativistic intervals instead of distances? This way you would probably need 8N minus something (probably something=10) coordinates, and you don’t even need to arbitrarily choose axes labeled “x,y,z,t”.
Each particle doesn’t exist only in one point of spacetime, but on an entire time-like curve (the worldline).
Each particle doesn’t exist only in one point of spacetime, but on an entire time-like curve (the worldline).