On the semantics of theory change

摘要: Katsuno and Mendelzon divide theory change, the problem of adding new information to a logical theory, into two types: revision update. We propose third type change: arbitration. The key idea is following: considered neither better nor worse than old represented by theory. simply one voice against set others already incorporated From this follows that arbitration should be commutative. First we define postulates then describe model-theoretic characterization for case propositional theories. also study weighted where different models can have weights.