UML (Unified Modeling Language) is the de facto standard model representation language in software engineering. We believe that automated contradiction detection and repair of UML become very important as UML has been widely used. In this paper, we propose a debugging system using logic programming paradigm for UML class diagram with class attributes, multiplicity, generalization relation and disjoint relation.

We propose a translation method of a UML class diagram into a logic program, and using a meta-interpreter we can find (set-inclusion-based) minimal sets of rules which leads to contradiction. Then, we use a minimal hitting set algorithm developed by one of the authors to show minimal sets of deletion of rules in order to avoid contradiction.