Modus ponens versus modus tollens associated with rough gradual decision rules induced from a decision table

We have proposed a fuzzy rough set approach to induce gradual decision rules from decision tables without using any fuzzy logical connectives. In this paper, we discuss the use of these gradual decision rules within modus ponens and modus tollens inference patterns. We show differences and similarities between modus ponens and modus tollens through representation theorems of modifier functions characterizing the inference patterns. Moreover, we prove that modus ponens and modus tollens are equivalent under suitable monotonicity conditions. Finally, we conclude this paper with a comparison between the linear regression analysis and the proposed approach.