$\forall$$T$:Type, $E$:($T$$\rightarrow$$T$$\rightarrow\mathbb{P}$).
\\[0ex]EquivRel($T$;$x$,$y$.$E$($x$,$y$)) $\Rightarrow$ ($\forall$$x$, $y$:$T$. Dec($E$($x$,$y$))) $\Rightarrow$ ($\forall$$u$, $v$:($x$,$y$:$T$//$E$($x$,$y$)). Dec($u$ = $v$))