From Deduction to Knowledge Representation

In this paper, we discuss why deduction is not sufficient for knowledge representation of programs with commonsense. Requirements of representation of incomplete, evolutive and conflicting knowledge led to a rise of alternative logic formalisms, dubbed nonmonotonic logics. Important features of nonmonotonic logic were discussed on the example of default logic - a role of assumptions in reasoning, use of fixpoint constructions as a formal tool for building a nonmonotonic semantics and, finally, computational aspects of nonmonotonic reasoning. This overview is completed by a presentation of our approach to updates. Updates are closely connected to nonmonotonic reasoning. We construct our approach for assumption based frameworks (and for default theories, as a consequence).