Oblivious Two-Way Finite Automata: Decidability and Complexity

  • Martin Kutrib
  • Andreas Malcher
  • Giovanni Pighizzini
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7256)


We investigate the descriptional complexity and decidability of obliviousness for two-way finite automata. In particular, we consider the simulation of two-way deterministic finite automata (\(\textrm{2DFA}\)s) by oblivious \(\textrm{2DFA}\)s, the simulation of oblivious \(\textrm{2DFA}\)s by sweeping \(\textrm{2DFA}\)s and one-way nondeterministic finite automata (\(\textrm{1NFA}\)s) as well as the simulation of sweeping \(\textrm{2DFA}\)s by \(\textrm{1NFA}\)s. In all cases exponential upper and lower bounds on the number of states are obtained for languages over an alphabet with at most four latters. Moreover, it is shown that obliviousness is decidable for \(\textrm{2DFA}\)s.


Regular Language Finite Automaton Input Symbol Descriptional Complexity Output Tape 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Martin Kutrib
    • 1
  • Andreas Malcher
    • 1
  • Giovanni Pighizzini
    • 2
  1. 1.Institut für InformatikUniversität GiessenGiessenGermany
  2. 2.Dipartimento di Informatica e ComunicazioneUniversità degli Studi di MilanoMilanoItaly

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