ISRO 2024

Question

Which f the following statements is FALSE?

1. The intersection of a regular language and a context-free language is context=free
2. The intersection of a regular language and context-free language is regular
3. The union of two context-free languages is context-free
4. The union of two regular languages is regular

Answer 1

Regular language and CFL are closed under union operation. So C, D is true.

Now, the intersection operation of CFL with regular language is closed, that is CFL itself. A is true.

Option $(B)$ is false here.