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On Random 3-sat

Published online by Cambridge University Press:  12 September 2008

A. El Maftouhi
Affiliation:
Laboratoire de Recherche en Informatique, Universite de paris-Sud, Bât. 490, 91405 Orsay Cedex, France
W. Fernandez De La Vega
Affiliation:
Laboratoire de Recherche en Informatique, Universite de paris-Sud, Bât. 490, 91405 Orsay Cedex, France

Abstract

Let S be a set of m clauses each containing three literals chosen at random in a set {p1, ¬p1,…,pn, ¬pn} of n propositional variables and their negations. Let be the set of all such S with m = cn for a fixed c > 0. We show, improving significantly over the first moment upper bound , that if m and n tend to infinity with , then almost all are unsatisfiable.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1995

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