$\forall$$M$:System.
\\[0ex]($\forall$$l$:IdLnk, ${\it tg}$:Id. $M$(source($l$)).dout($l$,${\it tg}$) $\subseteq\rho$ $M$(destination($l$)).din($l$,${\it tg}$))
\\[0ex]$\Rightarrow$ ($\forall$$i$:Id. finite{-}type(\{$l$:IdLnk$\mid$ destination($l$) $=$ $i$ \& $M$(source($l$)) sends on link $l$ \}))
\\[0ex]$\Rightarrow$ $M$ $\in$ \{$D$:Dsys$\mid$ Feasible($D$) \}