Lower bounds for randomized read-k-times branching programs

(Extended abstract)
  • Martin Sauerhoff
Complexity I

DOI: 10.1007/BFb0028553

Part of the Lecture Notes in Computer Science book series (LNCS, volume 1373)
Cite this paper as:
Sauerhoff M. (1998) Lower bounds for randomized read-k-times branching programs. In: Morvan M., Meinel C., Krob D. (eds) STACS 98. STACS 1998. Lecture Notes in Computer Science, vol 1373. Springer, Berlin, Heidelberg

Abstract

Randomized branching programs are a probabilistic model of computation defined in analogy to the well-known probabilistic Turing machines. In this paper, we contribute to the complexity theory of randomized read-k-times branching programs.

We first consider the case read-k-times = 1 and present a function which has nondeterministic read-once branching programs of polynomial size, but for which every randomized read-once branching program with two-sided error at most 27/128 is exponentially large. The same function also exhibits an exponential gap between the randomized read-once branching program sizes for different constant worst-case errors, which shows that there is no “probability amplification” technique for read-once branching programs which allows to decrease the error to an arbitrarily small constant by iterating probabilistic computations.

Our second result is a lower bound for randomized read-k-times branching programs with two-sided error, where k > 1 is allowed. The bound is exponential for k < clog n, c an appropriate constant. Randomized read-k-times branching programs are thus one of the most general types of branching programs for which an exponential lower bound result could be established.

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Copyright information

© Springer-Verlag 1998

Authors and Affiliations

  • Martin Sauerhoff
    • 1
  1. 1.Fachbereich InformatikUniversität DortmundDortmundGermany

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