文档介绍：Foundations of Description Logics
Sebastian Rudolph
Institute AIFB, Karlsruhe Institute of Technology, DE
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Abstract. This chapter panies the foundational lecture on Descrip-
tion Logics (DLs) at the 7th Reasoning Web Summer School in Galway,
Ireland, 2011. It introduces basic notions and facts about this family of
logics which has significantly gained in importance over the recent years
as these logics constitute the formal basis for today’s most expressive on-
tology languages, the OWL (Web Ontology Language) family.
We start out from some general remarks and examples demonstrating
the modeling capabilities of description logics as well as their relation
to first-order predicate logic. Then we begin our formal treatment by
introducing the syntax of DL knowledge bases es in three
parts: RBox, TBox and ABox. Thereafter, we provide the corresponding
standard model-theoretic semantics and give a glimpse of the alternative
way of defining the semantics via an embedding into first-order logic with
equality.
We continue with an overview of the naming conventions for DLs
before we delve into considerations about different notions of semantic
alikeness (concept and knowledge base equivalence as well as emulation).
These are crucial for investigating the expressivity of DLs and performing
normalization. We move on by reviewing knowledge representation ca-
pabilities brought about by different DL features and binations
as well as some model-theoretic properties associated thereto.
Subsequently, we consider typical reasoning tasks occurring in the
context of DL knowledge bases. We show how some of these tasks can
be reduced to each other, and have a look at different algorithmic ap-
proaches to realize automated reasoning in DLs.
Finally, we establish connections between DLs and OWL. We show
how DL knowledge bases can be expressed in OWL and, conversely, how
OWL modeling features can be translated into DLs.