Universal beliefs structures

Meier M. Universal beliefs structures. Bielefeld (Germany): Bielefeld University; 2002.The term "Beliefs Structures" is meant to serve as a generic term for mathematical structures that describe uncertainty in an interactive context, such as those that will appear in the sequel, namely, Kripke Structures, (K-) Type Spaces, and (Conditional) Possibility Structures. One of the central questions of this thesis is as to whether, for a class of beliefs structures, there exists a "largest" structure in this class that "contains" all the structures of that class. Such a structure is said to be "universal". Formulated in category theoretic terms, we are looking for a terminal object in a category (of beliefs structures)