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Formalising PFSQL queries using ŁΠ fuzzy logic†

Published online by Cambridge University Press:  14 December 2011

ALEKSANDAR PEROVIĆ ,
ALEKSANDAR TAKAČI  and
SRDJAN ŠKRBIĆ
ALEKSANDAR PEROVIĆ
Affiliation:
Faculty of Transportation and Traffic Engineering, University of Belgrade, Serbia Email: pera@sf.bg.ac.rs
ALEKSANDAR TAKAČI
Affiliation:
Faculty of Technology, University of Novi Sad, Serbia Email: stakaci@tf.uns.ac.rs
SRDJAN ŠKRBIĆ
Affiliation:
Faculty of Science, University of Novi Sad, Serbia Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia Email: shkrba@uns.ac.rs
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Abstract

Using the concept of a generalised priority constraint satisfaction problem, we previously found a way to introduce priority queries into fuzzy relational databases. The results were PFSQL (Priority Fuzzy Structured Query Language) together with a database independent interpreter for it. In an effort to improve the performance of the resolution of PFSQL queries, the aim of the current paper is to formalise PFSQL queries by obtaining their interpretation in an existing fuzzy logic. We have found that the ŁΠ logic provides sufficient elements. The SELECT line of PFSQL queries is semantically a formula of some fuzzy logic, and we show that such formulas can be naturally expressed in a conservative extension of the ŁΠ logic. Furthermore, we prove a theorem that gives the PSPACE containment for the complexity of finding a model for a given ŁΠ logic formula.

Type
Paper
Information
Mathematical Structures in Computer Science , Volume 22 , Issue 3 , June 2012 , pp. 533 - 547
Copyright
Copyright © Cambridge University Press 2011

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