$\forall$$A$:Type, ${\it eq}$:EqDecider($A$), $B$:($A$$\rightarrow$Type), $f$, $g$:$a$:$A$ fp$\rightarrow$ $B$($a$). l\_disjoint($A$;$f$.1;$g$.1) $\Rightarrow$ $f$ $\parallel$ $g$