On later considering COLOUR : blue , the algorithm adds it to D part , since it is contrastive for {e 2 , e 5 }, but will have failed to propagate COLOUR across fragments.
iA part considers values of an attribute in order of discriminatory power (Dale, 1989), defined in the present context as follows: Discriminatory power depends on the number of referents a property includes in its extension, and the number of distractors (U −R) it removes.