Since its introduction by Reiter in 1980 default logic has been widely studied for its potential as a knowledge representation mechanism. Recent results indicate that default logic not only can serve as a declarative knowledge representation tool but also has the potential to evolve into a practical high-level computational environment. This project develops fast systems for automated default reasoning including implementations for parallel and distributed environments. A systematic methodology of computing with default logic is also under development. Usefulness of default logic as a computational tool is demonstrated through a comprehensive experimentation with default theories describing combinatorial optimization problems. To support this experimentation effort, a tool to automatically generate large families of default theories, logic programs and propositional theories is implemented. Due to the declarative nature of default logic, this new programming tool, based on default logic, will be easy to use, will allow for fast prototyping and will be effective in a wide range of artificial intelligence applications. The testing system will become a standard benchmarking tool for automated reasoning based on default logic and related formalisms.
