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International Conference on Database and Expert Systems Applications

DEXA 1996: Database and Expert Systems Applications pp 224–233Cite as

The complexity of weak unification of bounded simple set terms

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Part of the book series: Lecture Notes in Computer Science ((LNCS,volume 1134))

Abstract

In this paper we consider the problem of weak unification of bounded simple set terms. Simple set terms are of the form {e 1, ..., e n}, 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. 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.

Work partially supported by a European Union grant under the EU-US project “DEUS EX MACHINA: non-determinism for deductive databases” and by a MURST project “Sistemi formali e strumenti per basi di dati evolute”.

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Author information

Authors and Affiliations

  1. DEIS, Univ. della Calabria, 87030, Rende, Italy

    Sergio Greco & Cristinel Mateis

  2. ISI-CNR, c/o DEIS - Univ. della Calabria, 87030, Rende, Italy

    Eugenio Spadafora

Authors
  1. Sergio Greco
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  2. Cristinel Mateis
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  3. Eugenio Spadafora
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Editor information

Roland R. Wagner Helmut Thoma

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© 1996 Springer-Verlag Berlin Heidelberg

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Greco, S., Mateis, C., Spadafora, E. (1996). The complexity of weak unification of bounded simple set terms. In: Wagner, R.R., Thoma, H. (eds) Database and Expert Systems Applications. DEXA 1996. Lecture Notes in Computer Science, vol 1134. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0034683

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  • DOI: https://doi.org/10.1007/BFb0034683

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  • Publisher Name: Springer, Berlin, Heidelberg

  • Print ISBN: 978-3-540-61656-6

  • Online ISBN: 978-3-540-70651-9

  • eBook Packages: Springer Book Archive

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