\begin{tabbing}
gluable2($A$;$I$;$l$;${\it tg}$)
\\[0ex]$\,\equiv$$_{\mbox{\scriptsize def}}$$\;\;$\=(destination($l$) $\in$ ma{-}interface{-}locs($I$) $\in$ Id)\+
\\[0ex]$\Rightarrow$ (rcv($l$,${\it tg}$) $\in$ ma{-}interface{-}dom($I$;destination($l$)) $\in$ Knd)
\\[0ex]$\Rightarrow$ ($A$ $\subseteq$r ma{-}interface{-}valtype($I$;destination($l$);rcv($l$,${\it tg}$)))
\-
\end{tabbing}