Inducing Integrity Constraints from Knowledge Bases

Integrity constraints are important logical tools for the general organization of knowledge. Integrity constraints (in short: ICs), which are commonly used in the eld of deductive databases, specify general regularities like \a son is not older than his father." They facilitate the organization of knowledge in expert systems and can speed up the query-response time signiicantly. This paper presents an approach for inductively generating compact integrity constraints from knowledge bases, represented in rst-order logic. To obtain the most powerful ICs, the huge space of potential ICs, which are principally consistent with a given knowledge base, is restricted by IC-schemes. IC-schemes specify ICs syntactically. The proposed method searches the resulting space of ICs eeciently by pruning away whole subspaces. The approach is also capable of detecting irregularities in \noisy" knowledge bases which might be inconsistent. Empirical results illustrate the appropriateness of this method for nding compact ICs in a reasonable period of time.