$\forall$$A$:Type, ${\it eq}$:EqDecider($A$), $f$, $g$:$a$:$A$ fp$\rightarrow$ Top, $L$:$A$ List.
\\[0ex]l\_disjoint($A$;1of($f$ $\oplus$ $g$);$L$) $\Leftrightarrow$ l\_disjoint($A$;1of($f$);$L$) \& l\_disjoint($A$;1of($g$);$L$)