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The verification problem for action logic programs with non-terminating behaviour is in general undecidable. In this paper, we consider a restricted setting in which the problem becomes decidable. On the one hand, we abstract from the actual execution sequences of a non-terminating program by considering infinite sequences of actions defined by a Büchi(More)
We describe Orel, a reasoning system for an ontology language which subsumes both the EL and the RL profile of the recently standardised web ontology language OWL 2. Orel performs consequence-driven reasoning on the database level which is always sound. It is guaranteed to be complete if the ontology is contained in one of the two profiles. We present the(More)
One of the major advantages of semantically annotating resources on Web is the facilitation of web services discovery. Languages based on OWL are prune to several problems for web services discovery due to the open-world assumption when handling incomplete information. Thus standard OWL reasoner are usually not suitable for the discovery purposes. The(More)
Extending ontology querying facilities with the epistemic operator provides practically useful additional functionalities like ontology introspection, integrity constraints checking, etc. In this paper, we present a practical system called EQuIKa capable of epistemic inferencing on OWL 2 DL Ontologies. It implements our recently developed reduction method(More)
The standard semantics employed for description logics (DLs) adheres to the open world assumption (OWA). On one hand, such an assumption facilitates a modeler to formally represent problem domains with out explicitly expressing full information, which sometimes is even not possible. This is probably one of the main reasons of founding the Web Ontology(More)
In this paper, we present a reasoner capable of epistemic inferences in SROIQ knowledge bases. We first identify some counter intuitive effects of imposing the traditional semantics in epistemic extensions of expressive description logics (DLs). Thus, we provide a revised downward compatible semantics with a more intuitive behavior in such cases. Based on(More)
A central and much debated topic in the Knowledge Representation and Reasoning community is how to combine open-world with closed-world formalisms, such as Description Logics (DLs) with Logic Programming. We propose an approach to defining the semantics of hybrid theories, composed of a DL and a Normal Logic Program (NLP) parts, which employs standard(More)