Structured Clusters: A Framework to Reason with Contradictory Interests

This paper presents a framework in which priorities in a belief base can be specified and used in the resolution of conflicts. Priorities are given in terms of a partial pre-order associated with the sentences in the base. When the new information is given the highest priority, it is accepted, thus complying with the success postulate of the AGM theory of belief revision. However, in general, priorities can be specified in a very flexible way and an input sentence placed anywhere in the previous ordering. The result or conclusion of a belief base can be computed into a sentence, allowing the method to be used in the reasoning of more complex structures where nodes in the structure are themselves prioritized bases. Embedded groups of prioritized bases are recursively resolved before the embedding structure is. The method combines reasoning about inconsistency and priorities in an elegant way.