Context-free languages: closed operations
Context-free language closure
If \( L \) and \( M \) are context-free languages, then the following are also context-free languages:
- \( L \cup M \)
- [operation 2]
- [operation 3]
In other words, context-free languages are closed under union, [operation 2] and [operation 3].
There are important operations under which context free languages are not closed. Can you remember them?