Abstract: A rough fuzzy set model was constructed in the incomplete fuzzy decision system by using an extended dominance relation. By the proposed rough fuzzy approximation, all ＂at least＂ and ＂at most＂ decision rules can be generated from the incomplete fuzzy deci

Key words: Incomplete fuzzy deeision system, Dominance relation, Rough fuzzy set, Decision rules, Relative reduet