  In action domains where agents may have erroneous beliefs, reasoning about
the effects of actions involves reasoning about belief change. In this paper,
we use a transition system approach to reason about the evolution of an agents
beliefs as actions are executed. Some actions cause an agent to perform belief
revision while others cause an agent to perform belief update, but the
interaction between revision and update can be non-elementary. We present a set
of rationality properties describing the interaction between revision and
update, and we introduce a new class of belief change operators for reasoning
about alternating sequences of revisions and updates. Our belief change
operators can be characterized in terms of a natural shifting operation on
total pre-orderings over interpretations. We compare our approach with related
work on iterated belief change due to action, and we conclude with some
directions for future research.
