文档介绍：On the Semantic Relationship between Datalog and
Description Logics
Markus Krötzsch1, Sebastian Rudolph2, and Peter H. Schmitt3
1 Oxford puting Laboratory, UK
2 Institute AIFB, Karlsruhe Institute of Technology, DE
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3 Institute for puter Science, Karlsruhe Institute of Technology, DE
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Abstract. Translations to (first-order) datalog have been used in a number of
inferencing techniques for description logics (DLs), yet the relationship between
the semantic expressivities of function-free Horn logic and DL is understood only
poorly. Although Description Logic Programs (DLP) have been described as DLs
in the “expressive intersection” of DL and datalog, it is unclear what an intersec-
tion of two syntactically parable logics is, even if both have a first-order
logic semantics. In this work, we offer a characterisation for DL fragments that
can be expressed, in a concrete sense, in datalog. We then determine the largest
such fragment for the DL ALC, and provide an outlook on the extension of our
methods to more expressive DLs.
1 Introduction
Ontologies and rules are two fundamental concepts in knowledge representation. Taking
ontologies as the basic modelling paradigm has led to the development of Description
Logics (DLs) with a wide range of essful knowledge representations languages. On
the other hand rules are the central notion in Logic Programming building on first-order
Horn logic. Both have been very prolific research areas and have recently received a
boost in the context of the Semantic Web. As references for the purposes of this paper
we point to [2] and [4]. Since decidability is an important concern for DL, function-free
first-order Horn logic “datalog” is of particular interest.
Since the semantic frameworks for DL and datalog are very close it is natural that
the munity started investigating the relationship between them. One direc-
tion explores how ei