$\forall$$A$:Type, $B$:($A$$\rightarrow$Type), ${\it eq}$:EqDecider($A$), $f_{1}$, $g_{1}$, $f_{2}$, $g_{2}$:$a$:$A$ fp$\rightarrow$ $B$($a$).
\\[0ex]$f_{2}$ $\parallel$ $g_{1}$ $\Rightarrow$ $f_{1}$ $\subseteq$ $g_{1}$ $\Rightarrow$ $f_{2}$ $\subseteq$ $g_{2}$ $\Rightarrow$ $f_{1}$ $\oplus$ $f_{2}$ $\subseteq$ $g_{1}$ $\oplus$ $g_{2}$