Hierarchical Linguistic Variables

The linguistic terms of a linguistic variable classify the numeric values of their universe. In that sense, they are categories which are defined over a space of values. In this work a hierarchical model of a linguistic variable is analyzed from the point of view of the principles of categorization and hierarchy theory. It is shown how several partial orders can be defined over the hierarchical model in correspondence with two different interpretations of the hierarchical structure of the linguistic variable. Several methods to obtain the fuzzy set which gives the semantic value of a linguistic term in this family of linguistic variables are studied.