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A fuzzy version of default logic

Kumar S. Ray (Indian Statistical Institute, Kolkata, India)
Arpan Chakraborty (North Carolina State University, Raleigh, North Carolina, USA)

International Journal of Intelligent Computing and Cybernetics

ISSN: 1756-378X

Article publication date: 29 March 2011




The importance of fuzzy logic (FL) in approximate reasoning, and that of default logic (DL) in reasoning with incomplete information, is well established. Also, the need for a commonsense reasoning framework that handles both these aspects has been widely anticipated. The purpose of this paper is to show that fuzzyfied default logic (FDL) is an attempt at creating such a framework.


The basic syntax, semantics, unique characteristics and examples of its complex reasoning abilities have been presented in this paper.


Interestingly, FDL turns out to be a generalization of traditional DL, with even better support for non‐monotonic reasoning.


The paper presents a generalized tool for commonsense reasoning which can be used for inference under incomplete information.



Ray, K.S. and Chakraborty, A. (2011), "A fuzzy version of default logic", International Journal of Intelligent Computing and Cybernetics, Vol. 4 No. 1, pp. 5-24.



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