$\forall$$i$:Id, $L$:IdLnk List, $k$:Knd.
\\[0ex]@$i$: $k$ sends only links in $L$ 
\\[0ex]realizes ${\it es}$.
\\[0ex]$\forall$$e$@$i$. kind($e$) $=$ $k$ $\Rightarrow$ ($\forall$$l$:IdLnk. $\neg$($l$ $\in$ $L$) $\Rightarrow$ sends($l$;$e$) $=$ nil $\in$ Msg List)