\newcommand{\al}{\square}
\newcommand{\nx}{\bigcirc}
+\everymath{\displaystyle}
+
\begin{document}
\begin{enumerate}
\item
$\xymatrix{
- \ar[dr]\\
- & *+[o][F-]{s_0}\\
- *+[o][F-]{nc_1} & & *+[o][F-]{nc_1}
+ & l_0 & l_1 & l_2 & l_3 & l_5 & l_6 & l_7\\
+ l_0\\
+ l_1\\
+ l_2\\
+ l_3\\
+ l_5\\
+ l_6\\
+ l_7
}$
\item
$\al(crit_0\veebar crit_1)$
\item
We define:\\
- $\displaystyle AP=\bigcup_{i\in N}\{lift_n, door_n,call_n\},
+ $ AP=\bigcup_{i\in N}\{lift_n, door_n,call_n\},
N=\{0, 1, 2, 3\}$
\begin{enumerate}
\item
- $\forall n\in N\al(door_m\ra lift_n)$
+ $\bigwedge_{n\in N}\al(door_m\ra lift_n)$
\item
- $\forall n\in N\al(call_n\ra\ev lift_n)$
+ $\bigwedge_{n\in N}\al(call_n\ra\ev(lift_n\wedge door_n))$
\item
$\al\ev lift_0$
\item
- $\al call_3\rightarrow\bigcirc lift_3$
+ $\al(call_3\rightarrow\bigcirc (lift_3\wedge door_3))$
\end{enumerate}
\item\strut\\
$\begin{array}{ll}