This process of logical minimization is conducted in a bottom-up fashion until no further stepwise reduction of Boolean expressions is possible. Con ider again the data on military regime failures presented above. Each of the rows with one cause present and two absent can be combinedwith rows with two causes present and one absent because all these rows have the same out- come(F)and each pair differs in only one causal condition Abc combines with ABc to produce Ac Abc combines with AbC to produce Ab aBc combines with ABc to produce Bc aBc combines with aBC to produce aB abC combines with AbC to produce bC abC combines with aBC to produce aC