16. 16
Regular Languages
Definition:
A language is regular if there is
FA such that
Observation:
All languages accepted by FAs
form the family of regular languages
L
M ( )MLL =
17. 17
{ }abba { }abbaab,,λ
}0:{ ≥nban
{ all strings with prefix }
ab
{ all strings without substring }
001
Examples of regular languages:
There exist automata that accept these
Languages (see previous slides).
{ }{ }*,: bawawa ∈
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There exist languages which are not Regular:
}0:{ ≥= nbaL nn
There is no FA that accepts such a language
(we will prove this later in the class)
Example:
