On the complexity of the multiplication method for monotone CNF/DNF dualization

  • Authors:
  • Khaled M. Elbassioni

  • Affiliations:
  • Max-Planck-Institut für Informatik, Saarbrücken, Germany

  • Venue:
  • ESA'06 Proceedings of the 14th conference on Annual European Symposium - Volume 14
  • Year:
  • 2006

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Abstract

Given the irredundant CNF representation ϕ of a monotone Boolean function f:{0,1}n{0,1}, the dualization problem calls for finding the corresponding unique irredundant DNF representation ψ of f. The (generalized) multiplication method works by repeatedly dividing the clauses of ϕ into (not necessarily disjoint) groups, multiplying-out the clauses in each group, and then reducing the result by applying the absorption law. We present the first non-trivial upper-bounds on the complexity of this multiplication method. Precisely, we show that if the grouping of the clauses is done in an output-independent way, then multiplication can be performed in sub-exponential time. (n|ψ|)o(radic;|φ|)|φ|O(logn). On the other hand, multiplication can be carried-out in quasi-polynomial time poly (n|ψ|)ċ|ϕ|o(log|ψ|), provided that the grouping is done depending on the intermediate outputs produced during the multiplication process.