Chomsky Hierarchy

The Chomsky Hierarchy: A Guide to Formal Language Theory

Introduction

The Chomsky hierarchy is a classification of formal languages based on the types of grammars that can generate them. It was developed by Noam Chomsky in the 1950s and has since become a fundamental concept in formal language theory.

Levels of the Chomsky Hierarchy

The Chomsky hierarchy divides formal languages into four levels, each of which is characterized by a different level of restriction on the grammar that can generate it:

• Type 0: Unrestricted grammars
• Type 1: Context-sensitive grammars
• Type 2: Context-free grammars
• Type 3: Regular grammars

Applications of the Chomsky Hierarchy

The Chomsky hierarchy has a wide range of applications in computer science and linguistics. It is used in the design of programming languages, compilers, and natural language processing systems.