Specifying and Generating Preferred Plans

In this paper, we address the problem of specify- ing and generating preferred plans using rich, qual- itative user preferences. We propose a logical lan- guage for specifying preferences over the evolution of states and actions associated with a plan. We provide a semantics for our first-order preference language in the situation calculus and prove that progression of our preference formulae preserves this semantics. This leads to the development of PPLAN, a bounded best-first search planner that computes preferred plans. Our preference language is amenable to integration with many existing plan- ners, and beyond planning, can be used to support arbitrary dynamical reasoning tasks.