**5**

## Context Free Grammar

**5.1 CONTEXT FREE GRAMMAR: DEFINITION AND EXAMPLES**

Q. Define context free grammar. Why is it called context free?

**Ans**. According to Chomsky Hierarchy, Context Free Grammar (CFG) is Type 2 Grammar.

In mathematical description we can describe it as

*Where all the production are in the form α → β, where α V*_{N}, i.e. set of non-terminals and /α/ = 1, i.e. there will be only one non-terminal at the left-hand-side and β V_{N} U Σ, i.e. β is a combination of non-terminals and terminals.

Before describing why this type of grammar is called ...