 Thus, under constraints such as these, we obtain something like a traditional concept language.In the limiting case where formula_18 for every feature, and thus every probability in a concept must be 0 or 1, the result is a feature language base on conjunction; that is, every concept that can be represented can then be described as a conjunction of features (and their negations), and concepts that cannot be described in this way cannot be represented.In Fisher's (1987) description of COBWEB, the measure he uses to evaluate the quality of the hierarchy is Gluck and Corter's (1985) category utility (CU) measure, which he re-derives in his paper.