I just ran across the following paper: Defining Z in Q

It uses another characterization of the integers inside the rationals that none of us listed, perhaps because it is so trivial. Namely, the integers are the complement of the set $\mathbb{Q}\setminus\mathbb{Z}$! Apparently this basic fact is put to good use in the paper.

I just ran across the following paper: Defining Z in Q

It uses another characterization of the integers inside the rationals that none of us listed, perhaps because it is so trivial. Namely, the integers are the complement of the set $\mathbb{Q}\setminus\mathbb{Z}$! Apparently this basic fact is put to good use in the paper.