Now showing items 1-20 of 20

    • Adding Weight to DL-Lite 

      Artale, A; Calvanese, D; Kontchakov, R; Zakharyaschev, M (CEUR-WS.org, 2009)
      In this paper we extend the logic DL-LiteNbool and its fragments with (i) role inclusions, (ii) qualified number restrictions and (iii) role disjointness, symmetry, asymmetry, reflexivity and irreflexivity constraints. We ...
    • The Complexity of Clausal Fragments of LTL 

      Artale, A; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (Springer, 2013)
      We introduce and investigate a number of fragments of propositional temporal logic LTL over the flow of time (Z, <). The fragments are defined in terms of the available temporal operators and the structure of the clausal ...
    • Complexity of reasoning over entity-relationship models? 

      Artale, A; Calvanese, D; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (Bozen-Bolzano University Press, 2007)
      We investigate the complexity of reasoning over various fragments of the Extended Entity-Relationship (EER) language, which include different combinations of the constructors for ISA between concepts and relationships, ...
    • Complexity of Reasoning over Temporal Data Models 

      Artale, A; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (Springer, 2010)
      We investigate the computational complexity of reasoning over temporal extensions of conceptual data models. The temporal conceptual models we analyse include the standard UML/EER constructs, such as isa between entities ...
    • Connecting Abstract Description Systems 

      Kutz, O; Wolter, F; Zakharyaschev, M (Morgan Kaufmann, 2002)
    • A Cookbook for Temporal Conceptual Data Modelling with Description Logics 

      Artale, A; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (Association for Computing Machinery (ACM), 2014)
      We design temporal description logics (TDLs) suitable for reasoning about temporal conceptual data models and investigate their computational complexity. Our formalisms are based on DL-Lite logics with three types of concept ...
    • The DL-Lite Family and Relations 

      Artale, A; Calvanese, D; Kontchakov, R; Zakharyaschev, M (Association for the Advancement of Artificial Intelligence / AI Access Foundation, 2009)
      The recently introduced series of description logics under the common moniker `DL-Lite' has attracted attention of the description logic and semantic web communities due to the low computational complexity of inference, ...
    • DL-Lite in the light of first-order logic 

      Artale, A; Calvanese, D; Kontchakov, R; Zakharyaschev, M (AAAI Press, 2007)
      The use of ontologies in various application domains, such as Data Integration, the Semantic Web, or ontology-based data management, where ontologies provide the access to large amounts of data, is posing challenging ...
    • DL-Lite with Temporalised Concepts, Rigid Axioms and Roles 

      Artale, A; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (Springer, 2009)
      We investigate the temporal extension of the description logic extslDL−Lite(RN)bool with the until operator on concepts, rigid (time-independent) and local (time-dependent) roles, and rigid TBox axioms. Using an embedding ...
    • E-connections of abstract description systems 

      Kutz, O; Lutz, C; Wolter, F; Zakharyaschev, M (Elsevier, 2004)
      Combining knowledge representation and reasoning formalisms is an important and challenging task. It is important because non-trivial AI applications often comprise different aspects of the world, thus requiring suitable ...
    • First-Order Rewritability of Temporal Ontology-Mediated Queries 

      Artale, A; Kontchakov, R; Kovtunova, A; Ryzhikov, V; Wolter, F; Zakharyaschev, M (AAAI Press, 2015)
      Aiming at ontology-based data access over temporal, in particular streaming data, we design a language of ontology-mediated queries by extending OWL 2 QL and SPARQL with temporal operators, and investigate rewritability ...
    • Interval temporal description logics 

      Artale, A; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (CEUR, 2015)
      We design interval temporal description logics based on the Horn fragment of DL-Lite extended with the Allen temporal operators. We identify two tractable fragments that are expressive enough to represent constraints arising ...
    • Past and Future of DL-Lite 

      Artale, A; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (AAAI Press, 2010)
      We design minimal temporal description logics that are capa- ble of expressing various aspects of temporal conceptual data models and investigate their computational complexity. We show that, depending on the required types ...
    • Reasoning over Extended ER Models 

      Artale, A; Calvanese, D; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (Springer, 2007)
      We investigate the computational complexity of reasoning over various fragments of the Extended Entity-Relationship (EER) language, which includes a number of constructs: isa between entities and relationships, disjointness ...
    • The Semantics of Modal Predicate Logic I: Counterpart-Frames 

      Kracht, M; Kutz, O (World Scientific, 2002)
      We introduce a new semantics for modal predicate logic, with respect to which a rich class of first-order modal logics is complete, namely all normal first-order modal logics that are extensions of free quantified K. This ...
    • Tailoring Temporal Description Logics for Reasoning over Temporal Conceptual Models 

      Artale, A; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (Springer, 2011)
      Temporal data models have been used to describe how data can evolve in the context of temporal databases. Both the Extended Entity-Relationship (EER) model and the Unified Modelling Language (UML) have been temporally ...
    • Temporal OBDA with LTL and DL-Lite 

      Artale, A; Kontchakov, R; Kovtunova, A; Ryzhikov, V; Wolter, F; Zakharyaschev, M (CEUR, 2014)
      We investigate various types of query rewriting over ontologies given in the standard temporal logic LTL as well as combinations of LTL with DL-Lite logics. In particular, we consider FO ( &lt; )- rewritings that can use ...
    • Temporalising tractable description logics 

      Artale, A; Kontchakov, R; Lutz, C; Wolter, F; Zakharyaschev, M (IEEE, 2007)
      It is known that for temporal languages, such as first-order LT L, reasoning about constant (time-independent) relations is almost always undecidable. This applies to temporal description logics as well: constant binary ...
    • Tractable interval temporal propo- sitional and description logics 

      Artale, A; Kontchakov, R; Ryzhikov, V; Zakharyaschev, M (AAAI Press, 2015)
      We design a tractable Horn fragment of the Halpern-Shoham temporal logic and extend it to interval-based temporal description logics, instance checking in which is P-complete for both combined and data complexity.
    • When Are Description Logic Knowledge Bases Indistinguishable? 

      Botoeva, E; Kontchakov, R; Ryzhikov, V; Wolter, F; Zakharyaschev, M (AAAI Press, 2015)
      Deciding inseparability of description logic knowledge bases (KBs) with respect to conjunctive queries is fundamental for many KB engineering and maintenance tasks including versioning, module extraction, knowledge exchange ...