Possibilistic Answer Set Programming Revisited
  Possibilistic answer set programming (PASP) extends answer set programming
(ASP) by attaching to each rule a degree of certainty. While such an extension
is important from an application point of view, existing semantics are not
well-motivated, and do not always yield intuitive results. To develop a more
suitable semantics, we first introduce a characterization of answer sets of
classical ASP programs in terms of possibilistic logic where an ASP program
specifies a set of constraints on possibility distributions. This
characterization is then naturally generalized to define answer sets of PASP
programs. We furthermore provide a syntactic counterpart, leading to a
possibilistic generalization of the well-known Gelfond-Lifschitz reduct, and we
show how our framework can readily be implemented using standard ASP solvers.
