New Polynomial Classes for Logic-Based Abduction
  We address the problem of propositional logic-based abduction, i.e., the
problem of searching for a best explanation for a given propositional
observation according to a given propositional knowledge base. We give a
general algorithm, based on the notion of projection; then we study
restrictions over the representations of the knowledge base and of the query,
and find new polynomial classes of abduction problems.
