Could anyone please help me understand how to answer this question? I know that
ID: 3549323 • Letter: C
Question
Could anyone please help me understand how to answer this question?
I know that for part a ( and correct me if I am wrong): an example of a string accepted in this language would be: aa ab ba bb
because u = Sigma^2={(aa),(ab),(ba),(bb)}
and an example of a string not in the language would be: a
but I don't understand the other parts.
Explanation / Answer
Answer you have given for (a) is correct.
(b) Example of a string that is in the language : w = epsilon (null)
then www = ww
Example of a string that is not in the language : w = a
aaa != aa
(c) Example of a string that is in the language : u = a, v = epsilon, w = a
uvw = a(epsilon)a = aa
wvu = a(epsilon)a = aa
Example of a string that is not in the language : u = a, v = epsilon, w = b
uvw = a(epsilon)b = ab
wvu = b(epsilon)a = ba
(c) Example of a string that is in the language : w = abab, u = ababab
uu = (ababab)(ababab) = abababababab
www = (abab)(abab)(abab) = abababababab
Example of a string that is not in the language : u = a,w = b
www = bbb
uu = aa