Embedding Description Logic Programs into Default Logic
  Description logic programs (dl-programs) under the answer set semantics
formulated by Eiter {\em et al.} have been considered as a prominent formalism
for integrating rules and ontology knowledge bases. A question of interest has
been whether dl-programs can be captured in a general formalism of nonmonotonic
logic. In this paper, we study the possibility of embedding dl-programs into
default logic. We show that dl-programs under the strong and weak answer set
semantics can be embedded in default logic by combining two translations, one
of which eliminates the constraint operator from nonmonotonic dl-atoms and the
other translates a dl-program into a default theory. For dl-programs without
nonmonotonic dl-atoms but with the negation-as-failure operator, our embedding
is polynomial, faithful, and modular. In addition, our default logic encoding
can be extended in a simple way to capture recently proposed weakly
well-supported answer set semantics, for arbitrary dl-programs. These results
reinforce the argument that default logic can serve as a fruitful foundation
for query-based approaches to integrating ontology and rules. With its simple
syntax and intuitive semantics, plus available computational results, default
logic can be considered an attractive approach to integration of ontology and
rules.
