We have not discussed closure properties of the recursive languages or the RE languages other than our discussion of complementation in Section $9.2.2.$ Tell whether the recursive languages and/or the RE languages are closed under the following operations. You may give informal, but clear, constructions to show closure.
- Union.
- Intersection.
- Concatenation.
- Kleene closure(star).
- Homomorphism.
- Inverse homomorphism.