“…Although all three algorithms are able to solve the reduction problem, the emphasis is somewhat different [8,15]. For example, the RS theory mainly focuses on the attribute reduction problem [23,28] and shows much potential in the multilabel learning [29,36], while the PCA is usually applied to the dimension reduction problem in the machine learning [9,16] and multi-objective optimization (MOO) [18,20]. What's more, the RS theory reduces attributes based on the partition of equivalence relation, which can be accomplished through the evaluation metric [30,31], like mutual information and information entropy [10,38].…”