Question

The class of context-free languages is not closed under ____________.

• A. union
• B. concatenation
• C. repeated concatenation
• D. intersection

Answer 1

The correct option is D intersection

The class of context-free languages is not closed under intersection.

A context-free language (CFL) is a language generated by a context-free grammar. Context-free languages have many applications in programming languages; in particular, most arithmetic expressions are generated by context-free grammars.

If L1 is a regular language and L2 is a context free language, then L1 ∩ L2 is a context free language.