Syntax of Default Logic
A default theory is a pair . is a set of logical formulae, called the background theory, that formalize the facts that are known for sure. is a set of default rules, each one being of the form:
According to this default, if we believe that is true, and each of is consistent with our current beliefs, we are led to believe that is true.
The logical formulae in and all formulae in a default were originally assumed to be first-order logic formulae, but they can potentially be formulae in an arbitrary formal logic. The case in which they are formulae in propositional logic is one of the most studied.
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Famous quotes containing the words default and/or logic:
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