3 FUZZY MEASURES
This discussion of fuzzy measures is adapted from
Eastman and Jiang (1996). The term fuzzy measure
refers to any set function which is monotonic with
respect to set membership (Dubois and Prade 1982;
see also Fisher, Chapter 13). Notable examples of
fuzzy measures include probabilities, the beliefs, and
plausibilities of Dempster-Shafer theory, and the
possibilities of fuzzy sets. Interestingly, if we consider
the process of standardisation in MCE to be one of
transforming criterion scores into set membership
statements (i.e. the set of suitable choices), then
standardised criteria are fuzzy measures.
A common trait of fuzzy measures is that they
follow DeMorgan’s Law in the construction of the
intersection and union operators (Bonissone and
Decker 1986). DeMorgan’s Law establishes a
triangular relationship between the intersection,
union, and negation operators such that: