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Alternating tree automata

From Wikipedia, the free encyclopedia
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In automata theory, an alternating tree automaton (ATA) is a generalisation of a nondeterministic tree automaton in the same way that an alternating finite automaton is a generalisation of a nondeterministic finite automaton (NFA).

Computational complexity

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The emptiness problem (deciding whether the language of an input ATA is empty) for ATAs, and therefore its complement, the universality problem, are EXPTIME-complete.[1] The membership problem (testing whether an input tree is accepted by an input AFA) is in PTIME[1].

References

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  1. 1 2 H. Comon, M. Dauchet, R. Gilleron, C. Löding, F. Jacquemard, D. Lugiez, S. Tison et M. Tommasi, Tree Automata Techniques and Applications (Theorem 7.5.1 and subsequent remark)