8
Star-free regular languages
•
Let
S
= {a,b,c}
(can be larger in general)
•
A regular language is defined by the grammar:
E ::=
;
E ::=
e |
a
|
b
|
c
E ::= E
[
E
E ::= E.E
E ::= E
*
•
A star-free regular language:
drop
E
*
, add
E
(need overline, not underline)