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.