NFA (nondeterministic finite automaton)

A Nondeterministic Finite Automaton (NFA) is a mathematical model used to recognize patterns or sets of strings within a language. Unlike a deterministic automaton, an NFA can choose to follow multiple possible paths simultaneously when reading an input, including transitions without consuming any input symbols (epsilon moves). If any of these paths reach an accepting state after processing the entire input, the NFA accepts the string. This flexibility makes NFAs a powerful and elegant way to describe complex pattern recognition tasks in fields like computer science and linguistics.