h-approximation: History-Based Approximation of Possible World Semantics
  as ASP
  We propose an approximation of the Possible Worlds Semantics (PWS) for action
planning. A corresponding planning system is implemented by a transformation of
the action specification to an Answer-Set Program. A novelty is support for
postdiction wrt. (a) the plan existence problem in our framework can be solved
in NP, as compared to $\Sigma_2^P$ for non-approximated PWS of Baral(2000); and
(b) the planner generates optimal plans wrt. a minimal number of actions in
$\Delta_2^P$. We demo the planning system with standard problems, and
illustrate its integration in a larger software framework for robot control in
a smart home.
