$D$ realizes ${\it es}$. $P$(${\it es}$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$$\forall$${\it D'}$:Dsys. $D$ $\subseteq$ ${\it D'}$ $\Rightarrow$ ($\forall$$w$:World, $p$:FairFifo. PossibleWorld(${\it D'}$;$w$) $\Rightarrow$ $P$(ES($w$)))