Alternating and empty alternating auxili
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Markus Holzer; Pierre McKenzie
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Article
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2003
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Elsevier Science
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English
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We consider variants of alternating auxiliary stack automata and characterize their computational power when the number of alternations is bounded by a constant or unlimited. In this way we get new characterizations of NP, the polynomial hierarchy, PSpace, and bounded query classes like co-DP =NL NP