Separation of distinct reduced fractions
= Separation of distinct reduced fractions
For distinct reduced fractions $p/q$ and $u/v$,
$$
\left|\frac pq-\frac uv\right|
=\frac{|pv-qu|}{qv}\geq\frac1{qv}.
$$
If $q>v$, this is strictly greater than $q^{-2}$.