Minimal Semantics for action Speci cations in PDL

In this paper we investigate minimal semantics for Propositional Dynamic Logic formulas. The goal is to be able to write action speciications in a declarative pre/post-condition style. The declarative speciication of actions comes with some well known problems: the frame problem, the qualiication problem and the ram-iication problem. We incorporate the assumptions that are inherent to both the frame and qualiication problem into the semantics of Dynamic Logic by deening preferences over Dynamic logic models. This gives us an intended semantics that, for each declarative action speciication, selects a unique meaning for each action.