$\forall$$D$:Dsys.
\\[0ex]Feasible($D$) $\Rightarrow$ ($\forall$$l$:IdLnk, ${\it tg}$:Id. M(source($l$)).dout($l$,${\it tg}$) $\subseteq\rho$ M(destination($l$)).din($l$,${\it tg}$))