##### Introduction to Grammer

**Grammar**** : **

A grammar G can be formally written as a 4-tuple (N, T, S, P) where − N or VN is a set of variables or non-terminal symbols. T or ∑ is a set of Terminal symbols. S is a special variable called the Start symbol, S ∈ N P is Production rules for Terminals and Non-terminals. A production rule has the form α → β, where α and β are strings on VN ∪ ∑ and least one symbol of α belongs to VN.