$\forall$${\it the\_w}$:World.
\\[0ex]FairFifo
\\[0ex]$\Rightarrow$ ($\forall$$e$:E, $l$:IdLnk. $\neg$loc($e$) $=$ source($l$) $\in$ Id $\Rightarrow$ sends($l$;$e$) $=$ nil $\in$ Msg\_sub($l$;${\it the\_w}$.M) List)