# Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu

# Approximate Reasoning

Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_5012

## Definition

Approximate reasoning is a deduction method which makes it possible to derive a conclusion on the basis of imprecisely characterized situation (quite often using linguistically specified fuzzy IF-THEN rules) and a new information that can also be imprecise. The basic scheme of approximate reasoning is the following:
$$\begin{array}{ll}\mathrm{Condition}:& \mathrm{IF}X\mathrm{is}{A}_1\mathrm{THEN}Y\mathrm{is}{B}_1\\ &\dots \dots \dots \dots \dots \dots \dots \dots \dots \dots \\ &\mathrm{IF}X\mathrm{is}{A}_m\mathrm{THEN}Y\mathrm{is}{B}_m\\ &\mathrm{Premise}:X\mathrm{is}{A}^{\prime}\\ &\dots \dots \dots \dots \dots \dots \dots \dots \dots \dots \\ &\mathrm{Conclusion}:Y\mathrm{is}{B}^{\prime}\end{array}$$
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## Recommended Reading

1. 1.
Klir GJ, Yuan B. Fuzzy sets and fuzzy logic: theory and applications. New York: Prentice-Hall; 1995.
2. 2.
Novák V, Lehmke S. Logical structure of fuzzy IF-THEN rules. Fuzzy Sets Syst. 2006;157(15):2003–29.
3. 3.
Novák V, Perfilieva I. On the semantics of perception-based fuzzy logic deduction. Int J Intell Syst. 2004;19:1007–31.
4. 4.
Novák V., Perfilieva I., and Močkoř J . Mathematical principles of fuzzy logic. Kluwer, Boston/Dordrecht, 1999.

## Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

## Authors and Affiliations

1. 1.Institute for Research and Applications of Fuzzy ModelingUniversity of OstravaOstravaCzech Republic