If
c
0
|
–
n
c
n
[
r
] for some
n
³
1, then
c
0
|
–
+
c
n
[
r
].
If
c
0
|
–
n
c
n
[
r
] for some
n
³
0, then
c
0
|
–
*
c
n
[
r
].
Example:
Consider
p
a
bc
|–
q
bc
[
1
:
p
a
®
q
], and
q
b
c
|–
r
c
[
2
:
q
b
®
r
].
Then,
p
a
b
c
|–
2
r
c
[
1 2
],
p
a
b
c
|–
+
r
c
[
1 2
],
p
a
b
c
|–
*
r
c
[
1 2
]
Sequence of Moves 2/2
15
/2
9