Supported by the National Natural Science Foundation of China under Grant Nos. 10161005, 19931020 (国家自然科学基金); the National Social Sicence Fundation of China under Grant No.02BZX046 (国家社会科学基金); the National Research Foundation for the Doctoral Program of H
An approach is introduced to derive specificity in default theories. Compared with other methods, themethod handles priority quite well and has lower complexity. Then the prioritized stationary semantic for defaultlogic is defined. The method can strengthen the cautious stationary default reasoning without increasing thecomputational complexity very much.