決定性プッシュダウンオートマトン; DPDA
出典:Wikipedia
出典:『Wikipedia』 (2011/04/25 02:10 UTC 版)
In automata theory, a pushdown automaton is a finite automaton with an additional stack of symbols; its transitions can take the top symbol on the stack and depend on its value, and they can add new top symbols to the stack. A deterministic pushdown automaton is effectively a particular type of pushdown automaton, namely ones that have at most one transition for the same combination of input symbol, state, and top stack symbol. Technically however, the notion of determinism for pushdown automata is more complicated than for finite automata as the transition is determined by both state and top stack symbol. This means that if we omit the stack from a deterministic pushdown automaton we usually end up with a nondeterministic finite automaton.