Now showing items 1-16 of 16

    • 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)
    • 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 ...
    • 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.