Two-way Quantum One-counter Automata
نویسندگان
چکیده
After the rst treatments of quantum nite state automata by Moore and Crutch eld and by Kondacs and Watrous, a number of papers study the power of quantum nite state automata and their variants. This paper introduces a model of two-way quantum one-counter automata (2Q1CAs), combining the model of two-way quantum nite state automata (2QFAs) by Kondacs and Watrous and the model of one-way quantum one-counter automata (1Q1CAs) by Kravtsev. We give the de nition of 2Q1CAs with well-formedness conditions. It is proved that 2Q1CAs are at least as powerful as classical two-way deterministic one-counter automata (2D1CAs), that is, every language L recognizable by 2D1CAs is recognized by 2Q1CAs with no error. It is also shown that several non-context-free languages including fanbn 2 j n 1g and fanb2 n j n 1g are recognizable by 2Q1CAs with bounded error.
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عنوان ژورنال:
- CoRR
دوره cs.CC/0110005 شماره
صفحات -
تاریخ انتشار 2001