Planning with Preferences using Logic Programming
  We present a declarative language, PP, for the high-level specification of
preferences between possible solutions (or trajectories) of a planning problem.
This novel language allows users to elegantly express non-trivial,
multi-dimensional preferences and priorities over such preferences. The
semantics of PP allows the identification of most preferred trajectories for a
given goal. We also provide an answer set programming implementation of
planning problems with PP preferences.
