Set
Predict
(
A
®
X
1
X
2
...
X
n
):
Illustration
X
1
X
2
X
n
…
a
y
X
1
X
2
X
n
…
a
…
e
e
e
…
Empty
(
X
1
X
2
...
X
n
)
=
Æ
vs.
Empty
(
X
1
X
2
...
X
n
) = {
e
}
a
Î
First
(
X
1
X
2
...
X
n
)
a
Î
Follow
(
A
)
e
Summary:
if
Empty
(
X
1
X
2
...
X
n
) = {
e
} then
Predict
(
A
®
X
1
X
2
...
X
n
) =
First
(
X
1
X
2
...
X
n
)
È
Follow
(
A
);
otherwise,
Predict
(
A
®
X
1
X
2
...
X
n
) =
First
(
X
1
X
2
...
X
n
)
A
S
x
z
a
= the current input symbol
S
x
A
or
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