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Chomsky Hierarchy

The Chomsky hierarchy is a classification of formal grammars that describes how languages are structured. It consists of four levels: 1. **Type 0**: Unrestricted grammars, capable of generating any language. 2. **Type 1**: Context-sensitive grammars, where production rules depend on surrounding symbols. 3. **Type 2**: Context-free grammars, allowing rules that replace a single symbol regardless of context. 4. **Type 3**: Regular grammars, which define simpler languages using fixed patterns or sequences. This hierarchy illustrates the complexity of language and how different grammar types can be used to express various levels of syntactic structure.

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    The Chomsky Hierarchy is a classification of formal languages based on their complexity. It includes four levels: 1. **Type 3 (Regular languages)**: Simple patterns, like those recognized by a finite automaton (e.g., regular expressions). 2. **Type 2 (Context-free languages)**: More complex structures, like those seen in programming languages (e.g., parse trees). 3. **Type 1 (Context-sensitive languages)**: Languages where context affects meaning, suitable for certain natural language computations. 4. **Type 0 (Recursively enumerable languages)**: The most complex, capable of expressing any computation but may not halt on some inputs. Each level can represent increasingly sophisticated structures and rules.