$\forall$$T$:Type, $L$:($T$ List), $R$:(\{$x$:$T$$\mid$ ($x$ $\in$ $L$)\} $\rightarrow$Realizer), $B$:Realizer.
\\[0ex]R{-}icompat($\oplus$$x$$\in$$L$.$R$($x$);$B$) $\Leftarrow\!\Rightarrow$ ($\forall$$x$$\in$$L$. R{-}icompat($R$($x$);$B$))