Abstract
According to Boolos & Jeffrey: Tarski"s indefinability theorem is a "negative result [...] poised, so to speak, between two positive results: on the one hand, that each of certain 'approximations' Vn to V is definible in arithmetic, and, on the other, that V itself is 'definible in second-order arithmetic'". We intend to take such 'approximations' as privileged object of study, scrutinizi…