The complexity of weak unification of bounded simple set terms

  • Sergio Greco
  • Cristinel Mateis
  • Eugenio Spadafora
Active and Temporal Aspects 2
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1134)


In this paper we consider the problem of weak unification of bounded simple set terms. Simple set terms are of the form {e1, ..., en}, where ei is a constant or a variable and are much used in deductive database systems such as \(\mathcal{L}\mathcal{D}\mathcal{L}\)and Coral. We consider a restricted form of unification, called “weak unification”, which is mainly used in the field of deductive databases where the database may contain both constants and variables and the program is “safe”. The main result of the paper is the detailed complexity analysis of the weak unification problem by providing a formula for determining the number of weak unifiers.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • Sergio Greco
    • 1
  • Cristinel Mateis
    • 1
  • Eugenio Spadafora
    • 2
  1. 1.DEISUniv. della CalabriaRendeItaly
  2. 2.ISI-CNRc/o DEIS - Univ. della CalabriaRendeItaly

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