from (21) we see that mathematically l(v) goes towards zero when v goes towards c0, but the physically smallest length which l(v) can get, is equal to elementary length r0!
Repeat this setence, but with the correct capitalization.
From (21) we see that mathematically l(v) goes towards zero when v goes towards c0, but the physically smallest length which l(v) can get, is equal to elementary length r0!