Abstract: The set valued information system was analyzed by dominanccbased rough set approach. By considering the dominance degree in terms of pair of objects, the concept of fuzzy dominance relation was proposed, the fuzzy technique was then employed in the dominanccbased rough set theory. hhe fuzzy dominanccbased rough set model was presented, then corresponding properties were discussed, from which we obtained new theory and practical approach to derive decision rules from the set valued decision system. Some numerical examples were employed to substantiate the conceptual arguments.

Key words: Set valued information system, Fuzzy dominance relation, Dominance-based rough set, Decision rule