Definition:
Let
L
be a language
.
L
is a
context-
free
language
(
CFL
)
if there exists a
context-free
grammar that
generates
L
.
Example:
L
=
{
a
n
b
n
:
n
³
0}
is a CFL.
Context-Free Language
(
CFL
)
Gist:
A language
generated
by a CFG.
G
= (
N
,
T
,
P
,
S
), where
N
= {
S
},
T
= {
a
,
b
},
P
= {
1
:
S
®
a
S
b
,
2
:
S
®
e
}
S
Þ
e
[
2
]
S
Þ
a
S
b
[
1
]
Þ
ab
[
2
]
S
Þ
a
S
b
[
1
]
Þ
aa
S
bb
[
1
]
Þ
aabb
[
2
]
…
L
(
G
)
=
{
a
n
b
n
:
n
³
0}
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