Abstract machine with limited memory.

In the theory of computation, a branch of theoretical computer science, a deterministic finite automaton—also known as deterministic finite acceptor, deterministic finite-state machine, or deterministic finite-state automaton—is a finite-state machine that accepts or rejects a given string of symbols, by running through a state sequence uniquely determined by the string.

In automata theory, a finite-state machine is called a deterministic finite automaton, if

In quantum computing, quantum finite automata or quantum state machines are a quantum analog of probabilistic automata or a Markov decision process.

In computer science, a deterministic acyclic finite state automaton,Jan Daciuk, Stoyan Mihov, Bruce Watson and Richard Watson.