Question

If \( L\) and \(\bar L\) are recursively enumerable, then L is

1. Regular
2. Context-free
3. Context-sensitive
4. Recursive

Answer 1

Correct Answer - Option 4 : Recursive

If a language is recursively enumerable but not recursive then its compliment will definitely be in CO-RE, hence not recursive.

Hence if a language in RE has its compliment in RE which means that language is recursive and so is its compliment.