Formal Languages Questions
The main difference between a non-deterministic finite automaton (NFA) and a context-free grammar (CFG) lies in their respective capabilities and structures.
An NFA is a computational model that consists of a finite set of states, an input alphabet, a transition function, an initial state, and a set of accepting states. It operates by reading input symbols and transitioning between states based on the current state and input symbol. NFAs are limited in their ability to handle non-determinism, meaning that for a given state and input symbol, there can be multiple possible transitions. They are primarily used to recognize regular languages.
On the other hand, a CFG is a formal grammar that consists of a set of production rules, non-terminal symbols, terminal symbols, and a start symbol. It is used to generate strings in a language by applying production rules to non-terminal symbols. CFGs are more expressive than NFAs as they can generate languages beyond regular languages, including context-free languages. They are commonly used in programming languages, natural language processing, and parsing.
In summary, the key difference is that NFAs are used to recognize regular languages and operate based on transitions between states, while CFGs are used to generate context-free languages and operate based on production rules applied to non-terminal symbols.