Using priorities to combine knowledge bases

Two or more companies, each with its own knowledge base, may merge. In that case one option is to merge the knowledge bases into one knowledge base. It can happen that some of the information contained in one or more knowledge bases may be in conflict with information in the other knowledge bases. There may be several such points of conflict and any information may be involved in several different such points of conflict. In that case, the integrator of the knowledge bases may prefer a certain claim to another in one conflict-point without necessarily preferring that claim in another conflict-point.Our work constructs a framework within which the consequences of a set of such preferences (expressed as priorities among sets of statements) can be computed. We give three types of semantics for priorities, two of which are shown to be equivalent to one another. The third type of semantics for priorities is shown to be more cautious than the other two. In terms of these semantics for priorities, we give a function for combining knowledge from different sources such that the combined knowledge is conflict-free and satisfies all the priorities.