It depends on whether the meaning of "exists" is, I think. By analogy to the finite universe (always dangerous in logic), it is like saying "we live in a sphere of diameter 4. We have proven (due some hypothetical variation of relativity) that all matter in the universe will never be able to move more than distance 1 from the original center of our existence. An object of length 3 can be mathematically described, but is theoretically impossible to construct." Or something.