--- /dev/null
+LATEX:=pdflatex
+DOCUMENTS:=e1.pdf
+
+.PHONY: all clean clobber
+
+all: $(DOCUMENTS)
+
+%.pdf: %.tex
+ $(LATEX) $(basename $<)
+ $(LATEX) $(basename $<)
+
+clobber:
+ $(RM) -v *.pdf
+
+clean:
+ $(RM) -v *.aux *.log
--- /dev/null
+\documentclass{article}
+
+\usepackage{a4wide}
+\usepackage{amssymb}
+\usepackage{amsmath}
+
+\newcommand{\ra}{\rightarrow}
+\newcommand{\un}{\text{ \textsf{U} }}
+\newcommand{\ev}{\lozenge}
+\newcommand{\al}{\square}
+\newcommand{\nx}{\bigcirc}
+
+\begin{document}
+\begin{enumerate}
+ \item
+ \item
+ \item
+ \item\strut\\
+ $\begin{array}{ll}
+ \phi_1=\ev\al c &
+ s_2\ra s_4\overline{\ra s_5}\\
+ \phi_2=\al\ev c &
+ s_2\ra s_4\overline{\ra s_5}\\
+ \phi_3=\nx\neg c\rightarrow\nx\nx c &
+ s_2\ra s_4\overline{\ra s_5}\\
+ \phi_4=\al a &
+ \text{Impossible. $a$ only holds in $s_1$ and in $s_5$.}\\
+ & \text{$s_1$ we can only leave through a state where $\neg a$}\\
+ & \text{$s_5$ we can not reach through $s_1$ without passing
+ through a $\neg a$ state}\\
+ \phi_5=a\un\al(b\vee c) &
+ s_1\ra s_4\overline{\ra s_5}\\
+ \phi_6=(\nx\nx b)\un(b\vee c) &
+ s_2\ra s_4\overline{\ra s_5}
+ \end{array}$
+\end{enumerate}
+\end{document}