$\forall$$T$:Type, $R$:($T$$\rightarrow$$T$$\rightarrow$Prop), $x$, $y$:$T$. ($x$ ($R$$^{\mbox{\scriptsize $\ast$}}$) $y$) $\Leftrightarrow$ ($x$ $R$\^{}+ $y$) $\vee$ $x$ $=$ $y$