The DUCTOR: A Theory Revision System for Propositional Domains

This paper presents the theory revision component of an integrated learning system called the DUCTOR. This component is capable of repairing imperfect domain theories by generalizing and/or specializing the rules responsible for incorrect classifications of examples. These repairs are made so as to minimize the changes to the original domain theory that will make the theory consistent with the set of examples. The theory revision system has been tested on a real-world medical domain theory, with very good results.