I'm currently having trouble with this one: $$L = \{a^m a^n \mid m, n\text{ is prime}\}$$
I really have no idea. I think it has something to do with Goldbach's conjecture making it impossible to prove, or did I miss something?
Asked
Active
Viewed 21 times
1
-
1Have you tried to apply the Pumping Lemma? – Lee Mosher Sep 26 '15 at 14:33
-
@BLAZE : I changed your "vertical bar" to \mid, which has proper spacing in this context and is standard. – Michael Hardy Sep 26 '15 at 15:19
-
@Michael Looks better, thanks, I will have to remember that syntax. – BLAZE Sep 26 '15 at 15:21
1 Answers
2
Hint. Prove that the language $L \cap (a^2)^*a$ is not regular.
J.-E. Pin
- 40,163
-
Hello! Thanks for the hint. If I understand correctly, I can assume that L is regular then L∩(a2)∗a is also regular. So if i can find a way to find that L∩(a2)∗a is not regular then we have a contradiction and I can say L is not regular? – V. Mack Sep 26 '15 at 16:04
-
Exactly... And you can use the fact that the only even prime is $2$. – J.-E. Pin Sep 26 '15 at 16:58
-