\begin{tabbing}
$\forall$\=${\it ds}$:(Id$\rightarrow$Type), ${\it da}$:(Id$\rightarrow$Knd$\rightarrow$Type), ${\it Aa}$, ${\it Ba}$, ${\it Ab}$, ${\it Bb}$:Type, ${\it Ca}$:Component(${\it ds}$;${\it da}$;${\it Aa}$;${\it Ba}$),\+
\\[0ex]${\it Cb}$:Component(${\it ds}$;${\it da}$;${\it Ab}$;${\it Bb}$).
\-\\[0ex]mux{-}component(${\it Ca}$;${\it Cb}$) $\in$ Component(${\it ds}$;${\it da}$;${\it Aa}$ + ${\it Ab}$;${\it Ba}$ + ${\it Bb}$)
\end{tabbing}