What is a characteristic of unrestricted grammar?

What is a characteristic of unrestricted grammar?

• A. It generates regular languages
• B. It is the least complex type of grammar
• C. It can represent any recursively enumerable language
• D. It requires specific structural rules

Answer: (C)

Unrestricted grammar is characterized by its ability to represent any recursively enumerable language, making it a powerful type of formal grammar in the Chomsky hierarchy. This type of grammar is not constrained by specific structural rules, allowing for a more flexible form of rewriting in the production rules. As a result, unrestricted grammars can generate languages that are more complex than regular or context-free languages. This ability to represent any recursively enumerable language means that unrestricted grammar can capture a broader range of syntactic structures, encompassing all grammars that can be accepted by a Turing machine. Because of this flexibility and power, unrestricted grammars serve as a foundational concept in both theoretical computer science and computational linguistics.

Unrestricted grammar is characterized by its ability to represent any recursively enumerable language, making it a powerful type of formal grammar in the Chomsky hierarchy. This type of grammar is not constrained by specific structural rules, allowing for a more flexible form of rewriting in the production rules. As a result, unrestricted grammars can generate languages that are more complex than regular or context-free languages.

This ability to represent any recursively enumerable language means that unrestricted grammar can capture a broader range of syntactic structures, encompassing all grammars that can be accepted by a Turing machine. Because of this flexibility and power, unrestricted grammars serve as a foundational concept in both theoretical computer science and computational linguistics.