Small Sweeping 2NFAs Are Not Closed Under Complement

  • Christos A. Kapoutsis
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4051)


A two-way nondeterministic finite automaton is sweeping (snfa) if its input head can change direction only on the end-markers. For every n, we exhibit a language that can be recognized by an n-state snfa but requires \(2^{\varOmega(n)}\) states on every snfa recognizing its complement.


Binary Relation Total Order Left Computation Generic String Left View 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Christos A. Kapoutsis
    • 1
  1. 1.Computer Science and Artificial Intelligence LaboratoryMassachusetts Institute of Technology 

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