\begin{tabbing}
$\forall$$a$:Id, $T$:Type, ${\it ds}$:$x$:Id fp$\rightarrow$ Type, $P$:Top, $a_{1}$:Id, $T_{1}$:Type, $d_{1}$:$x$:Id fp$\rightarrow$ Type, $P_{1}$:Top.
\\[0ex]${\it ds}$ $\parallel$ $d_{1}$
\\[0ex]$\Rightarrow$ $\neg$$a$ $=$ $a_{1}$
\\[0ex]$\Rightarrow$ (\=(\=with ds: ${\it ds}$\+\+
\\[0ex]action $a$:$T$
\\[0ex]precondition $a$(v) is
\\[0ex]$P$ s v)
\-\\[0ex]$\Vert\!+$ (\=with ds: $d_{1}$\+
\\[0ex]action $a_{1}$:$T_{1}$
\\[0ex]precondition $a_{1}$(v) is
\\[0ex]$P_{1}$ s v))
\-\-
\end{tabbing}