Displaying similar documents to “A space lower bound for acceptance by one-way Π 2 -alternating machines”

Translation from classical two-way automata to pebble two-way automata

Viliam Geffert, L'ubomíra Ištoňová (2010)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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We study the relation between the standard two-way automata and more powerful devices, namely, two-way finite automata equipped with some additional “pebbles” that are movable along the input tape, but their use is restricted (nested) in a stack-like fashion. Similarly as in the case of the classical two-way machines, it is not known whether there exists a polynomial trade-off, in the number of states, between the nondeterministic and deterministic two-way automata with nested pebbles....