$\forall$$T$:Type, ${\it eq}$:EqDecider($T$), ${\it as}$, ${\it bs}$:$T$ List.
\\[0ex]no\_repeats($T$;${\it as}$) $\Rightarrow$ no\_repeats($T$;l{-}union(${\it eq}$;${\it as}$;${\it bs}$))