ABSTRACT
Some attributes considered in rough set, such as symptom, color, and texture, are dierent from preference attributes, because their attribute values do not take preference information into consideration, but preference attributes do. e presence of preference attributes requires the consideration of dominance relations in data analysis. Object x dominates object y if the following holds:
1.Object x is at least as good as object y in all considered preference attributes. 2.Object x and y have identical or similar description in all considered prefer-
ence attributes.
