Redefining expectations in belief revision theories

In his 2001 book Change, Choice and Inference, Hans Rott offers a theory of belief change that utilizes a version of belief base revision. An outstanding feature of Rott's theory is that it places emphasis on the concept of expectation and argues that expectations should be distinguished from beliefs in a formal process. However, the distinction between beliefs and expectations turns out to be formally trivial under Rott's formalization, since in his theory, expectations correspond to nothing but some propositions on which old beliefs are based. In this thesis, I presuppose that belief and expectation are distinct concepts, and following this presupposition, I offer two new interpretations for the concept of expectation that may draw a substantial difference from the concept of belief.