Unification of bounded simple set terms in deductive databases

  • Sergio Greco
  • Cristinel Mateis
  • Eugenio Spadafora
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1154)


In this paper we consider the problem of unification of bounded simple set terms in the field of deductive databases. Simple set terms are of the form {e1,..., en}, where e i is a constant or a variable and are much used in deductive database systems such as \(\mathcal{L}\mathcal{D}\mathcal{L}\) and Coral. In this paper 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 results are: (a) the detailed complexity analysis of the weak unification problem by providing a formula for determining the number of weak unifiers, and (b) the invention of an optimal weak unification algorithm.


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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-CNR, c/o DEISUniv. della CalabriaRendeItaly

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