$\forall$$T$:Type.
\\[0ex]$T$ $\subseteq\rho$ $\mathbb{Z}$ $\Rightarrow$ ($\forall$${\it bs}$, ${\it as}$:$T$ List. no\_repeats($T$;${\it as}$) $\Rightarrow$ sorted(${\it as}$) $\Rightarrow$ no\_repeats($T$;merge(${\it as}$;${\it bs}$)))