$\forall$$A$:Type, $B$, $C$:($A$$\rightarrow$Type), ${\it eq}$:EqDecider($A$), $f$:$a$:$A$ fp$\rightarrow$ $B$($a$), $g$:$a$:$A$ fp$\rightarrow$ $C$($a$).
\\[0ex]($\forall$$x$:$A$. $x$ $\in$ dom($f$) $\Rightarrow$ $x$ $\in$ dom($g$) $\Rightarrow$ $B$($x$) $\subseteq\rho$ $C$($x$)) $\Rightarrow$ $f$ $\parallel$ $g$ $\in$ Prop