$\forall$$T$:Type, $R$:($T$$\rightarrow$$T$$\rightarrow\mathbb{P}$), $P$:($T$$\rightarrow\mathbb{P}$).
\\[0ex]($\forall$$x$, $y$:$T$. ($P$($y$) \& $R$($x$,$y$)) $\Rightarrow$ $P$($x$)) $\Rightarrow$ ($\forall$$x$, $y$:$T$. ($R$$\mid$$P$\^{}+($x$,$y$)) $\Leftarrow\!\Rightarrow$ ($R$\^{}+$\mid$$P$($x$,$y$)))