This question already has an answer here:
- Assume I have L1 which is a regular language, so we know since regular language is closed under complement, the complement of L1 is also a regular language.
- But let's say if the complement of L1 is a non-regular language, is it safe to conclude that L1 is a non-regular language as well?
Since I'm trying to prove a language L1 is not a regular language, and the pumping lemma doesn't work well with this case. But I can easily prove the complement of L1 is not regular, I'm wonder if that option is possible.