CREATE OWN LIBRARY

Design a DFA for Language: “At least one ‘a’”

∑ = {a, b}

 

Answer:

 

L = {a, ba, ab, aab, bba, …..}

 

 

Regular Expression RE1 = (a + b)* a(a + b)*

 

Grammar:

S → bS | aA

A → aA | bA | λ

 

Another regular expression we can write from the machine:

 

Regular Expression RE2:= b*a(a + b)* here L(RE1) = L(RE2) both regular expression are equivalent.

So, one language can have several regular expressions but all are equivalent.