Roos-Extension of Default Logic in Artificial Intelligence

One important defect of Reiter’s default logic is inability to reason by cases. To overcome the defect definition of Reiter’sextension. Roos presents a modified definition of a default extension that solves the problem. In this paper, we will discussthe properties of Roos-extension that similar to Reiter-extension, and will find some properties of Reiter-extension cannotstill correct to Roos-extension. We point out the difference of them, and Roos-extension offers a new idea for inference ofartificial intelligent, it can achieve a method to classify the information.