\begin{tabbing}
$\forall$\=$E$,$X_{1}$,$X_{2}$:Type, ${\it dE}$:EqDecider($E$), ${\it dL}$:EqDecider(IdLnk), ${\it pred?}$:($E$$\rightarrow$(?$E$)),\+
\\[0ex]${\it info}$:($E$$\rightarrow$((:Id $\times$ $X_{1}$) + (:(:IdLnk $\times$ $E$) $\times$ $X_{2}$))),
\\[0ex]$p$:(\=$\forall$$e$:$E$, $l$:IdLnk.\+
\\[0ex]$\exists$\=${\it e'}$:$E$\+
\\[0ex]($\forall$${\it e''}$:$E$. 
\\[0ex]($\uparrow$rcv?(${\it e''}$))
\\[0ex]$\Rightarrow$ (sender(${\it e''}$) = $e$)
\\[0ex]$\Rightarrow$ (link(${\it e''}$) = $l$)
\\[0ex]$\Rightarrow$ (((${\it e''}$ = ${\it e'}$) $\vee$ ${\it e''}$ $<$ ${\it e'}$) $\wedge$ (loc(${\it e'}$) = destination($l$) $\in$ Id)))),
\-\-\\[0ex]$e$:$E$, $l$:IdLnk.
\-\\[0ex]SWellFounded(($\neg$($\uparrow$first($y$))) c$\wedge$ ($x$ = pred($y$) $\in$ $E$))
\\[0ex]$\Rightarrow$ (\=receives(${\it dE}$; ${\it dL}$; ${\it pred?}$; ${\it info}$; $p$; $e$; $l$)\+
\\[0ex]$\in$ (\{$r$:$E$$\mid$ $\uparrow$rcv{-}from{-}on(${\it dE}$; ${\it dL}$; ${\it info}$; $e$; $l$; $r$)\}  List))
\-
\end{tabbing}