$\forall$$A$:Type, ${\it eq}$:EqDecider($A$), $f$, $g$:$a$:$A$ fp$\rightarrow$ Type, $a$:$A$. $f$ $\parallel$ $g$ $\Rightarrow$ ($f$ $\oplus$ $g$($a$)?Top $\subseteq$r $g$($a$)?Top)