Showing papers by "Franz Baader published in 2005"
Proceedings Article•
30 Jul 2005TL;DR: This work identifies a set of expressive means that can be added to EL without sacrificing tractability, and shows that basically all other additions of typical DL constructors to EL with GCIs make subsumption intractable, and in most cases even EXPTIME-complete.
Abstract: Recently, it has been shown that the small description logic (DL) EL, which allows for conjunction and existential restrictions, has better algorithmic properties than its counterpart FL0, which allows for conjunction and value restrictions. Whereas the subsumption problem in FL0 becomes already intractable in the presence of acyclic TBoxes, it remains tractable in EL even with general concept inclusion axioms (GCIs). On the one hand, we extend the positive result for EL by identifying a set of expressive means that can be added to EL without sacrificing tractability. On the other hand, we show that basically all other additions of typical DL constructors to EL with GCIs make subsumption intractable, and in most cases even EXPTIME-complete. In addition, we show that subsumption in FL0 with GCIs is EXPTIME-complete.
1,207 citations
01 Jan 2005
TL;DR: The vision of a Semantic Web has recently drawn considerable attention, both from academia and industry, and description logics are often named as one of the tools that can support this vision and thus help to make this vision reality.
Abstract: The vision of a Semantic Web has recently drawn considerable attention, both from academia and industry. Description logics are often named as one of the tools that can support the Semantic Web and thus help to make this vision reality.
484 citations
Proceedings Article•
09 Jul 2005TL;DR: This paper performs a detailed investigation of how the choice of the DL influences the complexity of the standard reasoning tasks executability and projection in the corresponding action formalism.
Abstract: We propose an action formalism that is based on description logics (DLs) and may be viewed as an instance of the Situation Calculus (SitCalc). In particular, description logic concepts can be used for describing the state of the world, and the pre- and post-conditions of actions. The main advantage of such a combination is that. on the one hand, the expressive power for describing world states and conditions is higher than in other decidable fragments of the Sitcalc, which are usually propositional. On the other hand, in contrast to the full Sitcalc, effective reasoning is still possible. In this paper, we perform a detailed investigation of how the choice of the DL influences the complexity of the standard reasoning tasks executability and projection in the corresponding action formalism. We also discuss semantic and computational problems in natural extensions of our framework.
181 citations
Proceedings Article•
01 Jan 2005
TL;DR: An analysis of how the choice of the DL inuences the complexity of standard reasoning tasks such as projection and executability, which are important for Web service discovery and composition, are analyzed.
Abstract: Motivated by the need for semantically well-founded and algorithmically managable formalisms for describing the functionality of Web services, we introduce an action formalism that is based on description logics (DLs), but is also rmly grounded on research in the reasoning about action community. Our main contribution is an analysis of how the choice of the DL inuences the complexity of standard reasoning tasks such as projection and executability, which are important for Web service discovery and composition.
59 citations
Journal Article•
TL;DR: In this article, the connection of two many-sorted theories is obtained by taking their disjoint union, and then connecting the two parts through connection functions that must behave like homomorphisms on the shared signature.
Abstract: Basically, the connection of two many-sorted theories is obtained by taking their disjoint union, and then connecting the two parts through connection functions that must behave like homomorphisms on the shared signature. We determine conditions under which decidability of the validity of universal formulae in the component theories transfers to their connection. In addition, we consider variants of the basic connection scheme.
29 citations
22 Jul 2005
TL;DR: Conditions under which decidability of the validity of universal formulae in the component theories transfers to their connection are determined and variants of the basic connection scheme are considered.
Abstract: Basically, the connection of two many-sorted theories is obtained by taking their disjoint union, and then connecting the two parts through connection functions that must behave like homomorphisms on the shared signature. We determine conditions under which decidability of the validity of universal formulae in the component theories transfers to their connection. In addition, we consider variants of the basic connection scheme.
15 citations
19 Sep 2005
TL;DR: This work generalizes decidability transfer results for so-called e-connections of modal logics by looking at pairs of connection functions that are adjoint pairs for partial orders defined in the component theories.
Abstract: In a previous paper, we have introduced a general approach for connecting two many-sorted theories through connection functions that behave like homomorphisms on the shared signature, and have shown that, under appropriate algebraic conditions, decidability of the validity of universal formulae in the component theories transfers to their connection. This work generalizes decidability transfer results for so-called e-connections of modal logics. However, in this general algebraic setting, only the most basic type of e-connections could be handled. In the present paper, we overcome this restriction by looking at pairs of connection functions that are adjoint pairs for partial orders defined in the component theories.
12 citations
TL;DR: A new concept constructor in Description Logics is introduced, an n-ary variant of the existential restriction constructor, which generalizes both the usual existential restrictions and so-called qualified number restrictions.
Abstract: Motivated by a chemical process engineering application, we introduce a new concept constructor in Description Logics (DLs), an n-ary variant of the existential restriction constructor, which generalizes both the usual existential restrictions and so-called qualified number restrictions We show that the new constructor can be expressed in , the extension of the basic DL by qualified number restrictions However, this representation results in an exponential blow-up By giving direct algorithms for extended with the new constructor, we can show that the complexity of reasoning in this new DL is actually not harder than the one of reasoning in Moreover, in our chemical process engineering application, a restricted DL that provides only the new constructor together with conjunction, and satisfies an additional restriction on the occurrence of roles names, is sufficient For this DL, the subsumption problem is polynomial
8 citations
25 May 2005
3 citations
Book•
01 Jan 2005
TL;DR: CERES in Many-Valued Logics: Implementing Efficient Resource Management for Linear Logic Programming and Layered Clausal Resolution in the Multi-modal Logic of Beliefs and Goals.
Abstract: CERES in Many-Valued Logics- A Decomposition Rule for Decision Procedures by Resolution-Based Calculi- Abstract DPLL and Abstract DPLL Modulo Theories- Combining Lists with Non-stably Infinite Theories- Abstract Model Generation for Preprocessing Clause Sets- Flat and One-Variable Clauses: Complexity of Verifying Cryptographic Protocols with Single Blind Copying- Applications of General Exact Satisfiability in Propositional Logic Modelling- BCiC: A System for Code Authentication and Verification- Ordered Resolution with Selection for - On a Semantic Subsumption Test- Suitable Graphs for Answer Set Programming- Weighted Answer Sets and Applications in Intelligence Analysis- How to Fix It: Using Fixpoints in Different Contexts- Reasoning About Systems with Transition Fairness- Entanglement - A Measure for the Complexity of Directed Graphs with Applications to Logic and Games- How the Location of * Influences Complexity in Kleene Algebra with Tests- The Equational Theory of ??, 0, 1,?+?, x, ?? Is Decidable, but Not Finitely Axiomatisable- A Trichotomy in the Complexity of Propositional Circumscription- Exploiting Fixable, Removable, and Implied Values in Constraint Satisfaction Problems- Evaluating QBFs via Symbolic Skolemization- The Dependency Pair Framework: Combining Techniques for Automated Termination Proofs- Automated Termination Analysis for Incompletely Defined Programs- Automatic Certification of Heap Consumption- A Formalization of Off-Line Guessing for Security Protocol Analysis- Abstraction-Carrying Code- A Verification Environment for Sequential Imperative Programs in Isabelle/HOL- Can a Higher-Order and a First-Order Theorem Prover Cooperate?- A Generic Framework for Interprocedural Analyses of Numerical Properties- Second-Order Matching via Explicit Substitutions- Knowledge-Based Synthesis of Distributed Systems Using Event Structures- The Inverse Method for the Logic of Bunched Implications- Cut-Elimination: Experiments with CERES- Uniform Rules and Dialogue Games for Fuzzy Logics- Nonmonotonic Description Logic Programs: Implementation and Experiments- Implementing Efficient Resource Management for Linear Logic Programming- Layered Clausal Resolution in the Multi-modal Logic of Beliefs and Goals
3 citations
01 Jan 2005
TL;DR: The Dagstuhl Seminar 05431 ``Deduction and Applications'' was held, and several participants presented their current research, and ongoing work and open problems were discussed.
Abstract: From 23.10.05 to 28.10.05, the Dagstuhl Seminar 05431 ``Deduction and Applications'' was held
in the International Conference and Research Center (IBFI),
Schloss Dagstuhl.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available.
Journal Article•
TL;DR: In this paper, a new concept constructor in Description Logics (DLs), an n-ary variant of the existential restriction constructor, which generalizes both the usual existential restrictions and so-called qualified number restrictions, was introduced.
Abstract: Motivated by a chemical process engineering application, we introduce a new concept constructor in Description Logics (DLs), an n-ary variant of the existential restriction constructor, which generalizes both the usual existential restrictions and so-called qualified number restrictions. We show that the new constructor can be expressed in , the extension of the basic DL by qualified number restrictions. However, this representation results in an exponential blow-up. By giving direct algorithms for extended with the new constructor, we can show that the complexity of reasoning in this new DL is actually not harder than the one of reasoning in . Moreover, in our chemical process engineering application, a restricted DL that provides only the new constructor together with conjunction, and satisfies an additional restriction on the occurrence of roles names, is sufficient. For this DL, the subsumption problem is polynomial.