6 - Describing Sets with Sets: Remarks on the Use and Interpretation of Set-valued Feature Structures

Abstract

This chapter reviews the use and interpretation of set-valued feature structures. According to the theory of simple feature structures, the unification of two structures produces the least upper bound of the two in regard to subsumption. The existence of least upper bounds is not really necessary for the feature structures as descriptions setup to work; it will be quite admissible for the unification of two structures to produce not one least upper bound but an option set consisting of two or more upper bounds which together span all the alternatives. Thereafter, set-descriptors reveal something of a universal nature about the described object, and something of an existential nature.