A system for computing constrained default logic extensions
The aim of this paper is to describe the algorithmic foundations of the part of the program Exten responsible for the computation of extensions in Constrained Default Logic. Exten is a system that computes extensions for various default logics.
The efficiency of the system is increased by pruning techniques for the search tree. We motivate and present these techniques, and demonstrate that they can cut down the size of the search tree significantly. Quite importantly, they complement well the recently developed stratification method. This technique has to be modified to work properly with Constrained Default Logic, and we show how this can be done.
Exten supports experimentation with default logic, allowing the user to set various parameters. Also it has been designed to be open to future enhancements, which are supported by its object-oriented design. Exten is part of our long-term effort to develop an integrated toolkit for intelligent information management based on nonmonotonic reasoning and belief revision methods.
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