Formalization of User Preferences, Obligations and Rights

Abstract

The aim of this chapter is to formalize user preferences, obligations, and rights in the context of Web information systems (WISs), and to indicate how this formalization can be used to reason about WIS specifications. This problem is approached on two levels of abstraction. On a high level a WIS is represented by a storyboard, which itself can be represented by an algebraic expression in a Kleene algebra with tests (KAT). Preferences can be formalized using the equational theory of KATs, which enable sophisticated propositional reasoning that can be applied to WIS personalization. Obligations and rights give rise to a propositional deontic logic. On a lower level of abstraction detailed state specifications are added using extended views. This amounts to replacing KATs by higher-order dynamic logic, using a higher-order deontic logic, and the formalization of proof obligations.