Peter Linz Edition 4 Exercise 1.2 Question 5 (Page No. 28)

Question

Let $Σ = ${$a, b$} and $L = ${$aa, bb$}. Use set notation to describe $L^c$.

Comments

Detailed Video Solution: https://www.youtube.com/watch?v=tdrGbsjQmDQ&list=PLIPZ2_p3RNHhXeEdbXsi34ePvUjL8I-Q9&index=3 

Answer 1

• At first draw a DFA for L.
• Then complement of DFA and find regular expr.

 

Answer 2

Let Σ = { a , b } and L = { aa , bb }

$L^c$ = Σ* - L

$L^c$ = { λ, a, b, ab , ba }  U { w : |w| > 2 , w ∈  Σ*}