Abstract
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.
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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Greco, S., Mateis, C., Spadafora, E. (1996). Unification of bounded simple set terms in deductive databases. In: Pedreschi, D., Zaniolo, C. (eds) Logic in Databases. LID 1996. Lecture Notes in Computer Science, vol 1154. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0031755
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DOI: https://doi.org/10.1007/BFb0031755
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