5 \section{Theory of Labelled Transition Systems
}
8 \subsection{Testing equivalences
}
11 ~ & Q_1 & Q_2 & Q_3 & Q_4 & Q_5
\cr
15 Q_4 &
0 &
0 &
0 &
1\cr
16 Q_5 &
0 &
0 &
0 &
0 &
1\cr
19 ~ & Q_1 & Q_2 & Q_3 & Q_4 & Q_5
\cr
23 Q_4 &
0 &
1 &
1 &
1\cr
24 Q_5 &
0 &
1 &
1 &
1 &
1\cr
27 ~ & Q_1 & Q_2 & Q_3 & Q_4 & Q_5
\cr
31 Q_4 &
0 &
1 &
1 &
1\cr
32 Q_5 &
0 &
1 &
1 &
1 &
1\cr
34 \item You can discriminate $Q_1$ from all the others by running the
35 trace $a
\rightarrow c$. $Q_2$ can be discriminated from the
36 rest by running $a
\rightarrow b
\rightarrow c$ because
37 $Q_3,Q_4$ and $Q_5$ may refuse the last $c$. To
38 discriminate $Q_3$ you can run $a
\rightarrow c$ since
39 $Q_4$ and $Q_5$ may refuse $c$. To discriminate $Q_4$ you need
40 to be able to go back. You can then discriminate by running
41 $a
\rightarrow c$ and then go back and run $b
\rightarrow c$.
42 This trace can only be accepted by $Q_4$.
44 ~ & Q_1 & Q_2 & Q_3 & Q_4 & Q_5
\cr
48 Q_4 &
0 &
1 &
1 &
1\cr
49 Q_5 &
0 &
1 &
1 &
1 &
1\cr
53 ~ & Q_1 & Q_2 & Q_3 & Q_4 & Q_5
\cr
57 Q_4 &
0 &
0 &
0 &
1\cr
58 Q_5 &
0 &
0 &
0 &
1 &
1\cr
60 \item All processes as explained in $d)$.
62 i
\setminus s & Q_1 & Q_2 & Q_3 & Q_4 & Q_5
\cr
63 Q_1 &
1 &
0 &
0 &
0 &
0\cr
64 Q_2 &
1 &
1 &
1 &
1 &
1\cr
65 Q_3 &
1 &
1 &
1 &
1 &
1\cr
66 Q_4 &
1 &
1 &
1 &
1 &
1\cr
67 Q_5 &
1 &
1 &
1 &
1 &
1\cr
72 \subsection{Testing equivalences
}
75 ~ & P_1 & P_2 & P_3 & P_4
\cr
79 P_4 &
0 &
0 &
0 &
1\cr
82 ~ & P_1 & P_2 & P_3 & P_4
\cr
86 P_4 &
0 &
1 &
1 &
1\cr
88 \item Trace $a
\rightarrow b
\rightarrow c$ may refuse in $P_3$ and $P_4$
89 but not in $P_2$. $P_3$ and $P_4$ can only be distinguished if
90 you are allowed to go back. If the trace $a
\rightarrow
91 b
\rightarrow c$ accepts you can go back to the state after $a$
92 and try $b
\rightarrow d$. This might only accept in $P_3$.
94 ~ & P_1 & P_2 & P_3 & P_4
\cr
98 P_4 &
0 &
0 &
1 &
1\cr
101 \item $
\bordermatrix{
102 i
\setminus s& P_1 & P_2 & P_3 & P_4
\cr
103 P_1 &
1 &
0 &
0 &
0\cr
104 P_2 &
0 &
1 &
0 &
0\cr
105 P_3 &
0 &
0 &
1 &
0\cr
106 P_4 &
0 &
0 &
1 &
1\cr
109 $P_1=
\xymatrix@C=
1pc@R=
1pc
{
111 & *+
[o
][F-
]{s_0
}\ar[d
]^a\\
112 & *+
[o
][F-
]{s_1
}\ar[d
]^b\\
113 & *+
[o
][F-
]{s_2
}\ar[d
]^c\\
116 $P_2=
\xymatrix@C=
1pc@R=
1pc
{
118 & *+
[o
][F-
]{s_0
}\ar[d
]^a\\
119 & *+
[o
][F-
]{s_1
}\ar[d
]^b\\
120 & *+
[o
][F-
]{s_2
}\ar[dl
]_c
\ar[dr
]^d\\
121 *+
[o
][F-
]{s_3
} & & *+
[o
][F-
]{s_4
}\\
123 $P_3=
\xymatrix@C=
1pc@R=
1pc
{
125 & *+
[o
][F-
]{s_0
}\ar[d
]^a\\
126 & *+
[o
][F-
]{s_1
}\ar[dl
]_b
\ar[dr
]^b\\
127 *+
[o
][F-
]{s_2
}\ar[d
]^c & & *+
[o
][F-
]{s_3
}\ar[d
]^d\\
128 *+
[o
][F-
]{s_4
} & & *+
[o
][F-
]{s_5
}\\
130 $P_4=
\xymatrix@C=
1pc@R=
1pc
{
132 & *+
[o
][F-
]{s_0
}\ar[dl
]_a
\ar[dr
]^a\\
133 *+
[o
][F-
]{s_2
}\ar[d
]^b & & *+
[o
][F-
]{s_3
}\ar[d
]^b\\
134 *+
[o
][F-
]{s_4
}\ar[d
]^c & & *+
[o
][F-
]{s_5
}\ar[d
]^d\\
135 *+
[o
][F-
]{s_6
} & & *+
[o
][F-
]{s_7
}
140 \subsection{Testing equivalences
}
141 \begin{enumerate
}[a)
]
144 \sigma\in traces(p)
\leftrightarrow
145 p
\text{ \bf after
}\sigma\text{ \bf refuses
}\emptyset\\
146 \sigma\in traces(p)
\leftrightarrow
147 \exists p':p
\overset{\sigma}{\Rightarrow}p'
\text{ and
}\forall a
\in
148 \emptyset:p'
\cancel{\overset{a
}{\rightarrow}} & &
2.\\
149 \sigma\in traces(p)
\leftrightarrow
150 \exists p':p
\overset{\sigma}{\Rightarrow}p'\\
151 \sigma\in \
{\sigma\in L^*|p
\overset{\sigma}{\Rightarrow}\
}\leftrightarrow
152 \exists p':p
\overset{\sigma}{\Rightarrow}p'& &
\square\\
156 p
\text{ \bf after
}\sigma\text{ \bf refuses
} A
\leftrightarrow
157 \sigma\cdot A
\in Ftraces(p)\\
158 \exists p':p
\overset{\sigma}{\Rightarrow}p'
\text{ and
}\forall a
\in
159 A:p'
\cancel{\overset{a
}{\rightarrow}} \leftrightarrow
160 \sigma\cdot A
\in Ftraces(p) & &
2.\\
161 \exists p':p
\overset{\sigma}{\Rightarrow}p'
\text{ and
}\forall a
\in
162 A:p'
\cancel{\overset{a
}{\rightarrow}} \leftrightarrow
163 \sigma\cdot A
\in \
{\psi\in(L
\cup
164 \mathcal{P
}(L))^*|p
\overset{\sigma}{\Rightarrow}\
} & &
4.\\
175 \subsection{Testing equivalences
}
176 \begin{enumerate
}[a)
]
177 \item $Q:=
\xymatrix@C=
1pc@R=
1pc
{
179 & *+
[o
][F-
]{s_0
}\ar@/_/
[d
]_a\\
180 & *+
[o
][F-
]{s_1
}\ar@/_/
[u
]_b
\ar@/_/
[d
]_a\\
181 & *+
[o
][F-
]{s_2
}\ar@/_/
[d
]_a
\ar@/_/
[u
]_b\\
182 &
\ldots\ar@/_/
[u
]_b\\
184 $P:=
\xymatrix@C=
1pc@R=
1pc
{
186 & *+
[o
][F-
]{s_0
}\ar@/_/
[d
]_a
\ar[r
]^
\tau & *+
[o
][F-
]{s_0
}\ar@(r,u)
[]_b\\
187 & *+
[o
][F-
]{s_1
}\ar@/_/
[u
]_b
\ar@/_/
[d
]_a
\ar@/_/
[ur
]_
\tau\\
188 & *+
[o
][F-
]{s_2
}\ar@/_/
[d
]_a
\ar@/_/
[u
]_b
\ar@/_1pc/
[uur
]_
\tau\\
189 &
\ldots\ar@/_/
[u
]_b
\ar@/_2pc/
[uuur
]_
\tau\\
194 \subsection{Testing equivalences
}