Αναπαράσταση γνώσης: επεκτάσεις στην αλλαγή πεποιθήσεων ; Knowledge representation: belief change extensions

Belief Change is an area that studies and standardizes several reasoning processes. However, the problems it has to confront rest in the wider area of Knowledge Representation.In the mid-1980s and after a transition eort to more systematic and mathematical approaches, the Belief Change gets into its nal form. The term “change” splits in three wide subgroups: expansion, contraction and revision. The expansion regards the collection of new information (belief expansion), while contraction concerns the loss of information. Finally, the revision explains the partial or total change in our beliefs, deriving from the appearance of new information.Every Change process is coupled with several rational postulates. Those were mainly formulated to group, classify and constrain our reasoning. Apart from the change formulas and the postulates mentioned above, in the eld of Belief Change there are other important – additional processes. One of the most known and useful is the Iterated Revision. While the simple Revision explains conditions that are induced from the emergence of one and only information, the Iterated Revision claries cases of learning through the spectrum of successive beliefs.The present dissertation is classied in three major categories. The rst one concerns the systematic study of several methods and techniques found in the international bibliography. The second incorporates our main contribution in research and our propositions with regard in open problems of the Belief Change. More specically, the initial stage of our research is an eort to connect the revision with the iterated belief revision. This connection is achieved with the introduction of a new postulate called “iterated recovery postulate”. It is also established that the iterated recovery postulate (IR) can be used in many cases where the second postulate DP2, by Darwiche and Pearl, is qualied as rather strong. Moreover, we prove hereby that the postulate is sound and complete through the Adam Grove’s System of Spheres.Our research continues to ...