Small is Again Beautiful in
Description Logics
Franz Baader
TU Dresden, Germany
Dresden
© Franz Baader
one of the origins
of DLs
Semantic networks
[Quillian, 1967]
Animal
IS-A
Frog
IS-A
Kermit
Dresden
has-color
Green
has-color
sits-on
Leaf
has-part
Tree
© Franz Baader
Problems
with Semantic Networks
Dresden
© Franz Baader
Ambiguities
in Semantic Networks
Animal
IS-A
Frog
Dresden
color
Green
© Franz Baader
Ambiguities
resolved in DLs
Animal
IS-A
Frog
Dresden
color
Green
© Franz Baader
Description logic system
Dresden
structure
© Franz Baader
Complexity
Dresden
of reasoning
tractability barrier
© Franz Baader
Ways out
of this dilemma
expressive DL
sound, but incomplete
tractable algorithms
inexpressive DL
sound and complete
tractable algorithms
Dresden
expressive DL
sound and complete
intractable algorithms
approach followed
by main-stream DL
research in the last
15 years
© Franz Baader
Ways out
of this dilemma
expressive DL
sound, but incomplete
tractable algorithms
inexpressive DL
sound and complete
tractable algorithms
Dresden
expressive DL
sound and complete
intractable algorithms
© Franz Baader
Description Logics
Dresden
research of the last 20 years
© Franz Baader
Light-weight DLs
•
•
subsumption and classification
tractable
sufficient expressive power for
life-science ontologies
Dresden
© Franz Baader
Value restrictions vs existential restrictions in DLs
Dresden
© Franz Baader
Dresden
© Franz Baader
Formal semantics
Dresden
© Franz Baader
Subsumption
Dresden
© Franz Baader
Complexity of subsumption
Dresden
© Franz Baader
Extension
Dresden
© Franz Baader
Dresden
© Franz Baader
Extension
Dresden
© Franz Baader
Extension
Dresden
© Franz Baader
CEL
Dresden
© Franz Baader
Light-weight DLs
•
•
query answering using
relational database systems
sufficient expressive power to
capture conceptual modelling
formalisms
Dresden
© Franz Baader
Dresden
© Franz Baader
Conjunctive query
Dresden
© Franz Baader
Query answering
Dresden
© Franz Baader
Query answering
Dresden
© Franz Baader
Query answering
Dresden
© Franz Baader
Dresden
© Franz Baader
Dresden
© Franz Baader
Questions?
Dresden
© Franz Baader