7 found
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  1.  29
    Logical Foundations and Complexity of 4QL, a Query Language with Unrestricted Negation.Jan Maluszyński & Andrzej Szalas - 2011 - Journal of Applied Non-Classical Logics 21 (2):211-232.
    The paper discusses properties of 4QL, a DATALOG⌉⌉-like query language, originally outlined by Maluszyński and Szalas. 4QL allows one to use rules with negation in heads and bodies of rules. It is based on a simple and intuitive semantics and provides uniform tools for “lightweight” versions of known forms of nonmonotonic reasoning. Negated literals in heads of rules may naturally lead to inconsistencies. On the other hand, rules do not have to attach meaning to some literals. Therefore 4QL is founded (...)
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  2.  18
    Converse-PDL with Regular Inclusion Axioms: A Framework for MAS Logics.Barbara Dunin-Kęplicz, Linh Anh Nguyen & Andrzej Szalas - 2011 - Journal of Applied Non-Classical Logics 21 (1):61-91.
    In this paper we study automated reasoning in the modal logic CPDLreg which is a combination of CPDL and REGc. The logic CPDL is widely used in many areas, including program verification, theory of action and change, and knowledge representation. On the other hand, the logic REGc is applicable in reasoning about epistemic states and ontologies. The modal logic CPDLreg can serve as a technical foundation for reasoning about agency. Even very rich multi-agent logics can be embedded into CPDLreg via (...)
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  3.  12
    On an Automated Translation of Modal Proof Rules Into Formulas of the Classical Logic.Andrzej Szalas - 1994 - Journal of Applied Non-Classical Logics 4 (2):119-127.
  4.  47
    Approximate Databases: A Support Tool for Approximate Reasoning.Patrick Doherty, Martin Magnusson & Andrzej Szalas - 2006 - Journal of Applied Non-Classical Logics 16 (1-2):87-117.
    This paper describes an experimental platform for approximate knowledge databases called the Approximate Knowledge Database, based on a semantics inspired by rough sets. The implementation is based upon the use of a standard SQL database to store logical facts, augmented with several query interface layers implemented in JAVA through which extensional, intensional and local closed world nonmonotonic queries in the form of crisp or approximate logical formulas can be evaluated tractably. A graphical database design user interface is also provided which (...)
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  5.  12
    Towards Incorporating Background Theories Into Quantifier Elimination.Andrzej Szalas - 2008 - Journal of Applied Non-Classical Logics 18 (2-3):325-340.
    In the paper we present a technique for eliminating quantifiers of arbitrary order, in particular of first-order. Such a uniform treatment of the elimination problem has been problematic up to now, since techniques for eliminating first-order quantifiers do not scale up to higher-order contexts and those for eliminating higher-order quantifiers are usually based on a form of monotonicity w.r.t implication and are not applicable to the first-order case. We make a shift to arbitrary relations “ordering” the underlying universe. This allows (...)
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  6.  11
    Second-Order Reasoning in Description Logics.Andrzej Szalas - 2006 - Journal of Applied Non-Classical Logics 16 (3-4):517-530.
    Description logics refer to a family of formalisms concentrated around concepts, roles and individuals. They belong to the most frequently used knowledge representation formalisms and provide a logical basis to a variety of well known paradigms. The main reasoning tasks considered in the area of description logics are those reducible to subsumption. On the other hand, any knowledge representation system should be equipped with a more advanced reasoning machinery. Therefore in the current paper we make a step towards integrating description (...)
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  7.  5
    Foreword.Ewa Orlowska, Alberto Policriti & Andrzej Szalas - 2006 - Journal of Applied Non-Classical Logics 16 (3-4):249-250.