Meghyn Bienvenu

Learn More
Consistent query answering is a standard approach for producing meaningful query answers when data is inconsistent. Recent work on consistent query answering in the presence of ontologies has shown this problem to be intractable in data complexity even for ontologies expressed in lightweight description logics. In order to better understand the source of(More)
There is a new trend to use Datalog-style rule-based languages to specify modern distributed applications, notably on the Web. We introduce here such a language for a distributed data model where peers exchange messages (i.e. logical facts) as well as rules. The model is formally defined and its interest for distributed data management is illustrated(More)
In this paper, we address the problem of specifying and generating preferred plans using rich, qualitative user preferences. We propose a logical language for specifying non-Markovian preferences over the evolution of states and actions associated with a plan. The semantics for our first-order preference language is defined in the situation calculus. Unlike(More)
Prime implicates and prime implicants have proven relevant to a number of areas of artificial intelligence, most notably abductive reasoning and knowledge compilation. The purpose of this paper is to examine how these notions might be appropriately extended from propositional logic to the modal logic K. We begin the paper by considering a number of(More)
Two-way regular path queries (2RPQs) have received increased attention recently due to their ability to relate pairs of objects by flexibly navigating graph-structured data. They are present in property paths in SPARQL 1.1, the new standard RDF query language, and in the XML query language XPath. In line with XPath, we consider the extension of 2RPQs with(More)
In this paper, we present a new normal form for concept expressions in the description logic ALC which is based on a recently introduced notion of prime implicate. We show that concepts in prime implicate normal form enjoy a number of desirable properties which make prime implicate normal form interesting from the viewpoint of knowledge compilation. In(More)
<i>Ontology-based data access</i> is concerned with querying incomplete data sources in the presence of domain-specific knowledge provided by an ontology. A central notion in this setting is that of an <i>ontology-mediated query</i>, which is a database query coupled with an ontology. In this paper, we study several classes of ontology-mediated queries,(More)
It is a classic result in database theory that conjunctive query (CQ) answering, which is NP-complete in general, is feasible in polynomial time when restricted to acyclic queries. Subsequent results identified more general structural properties of CQs (like bounded treewidth) which ensure tractable query evaluation. In this paper, we lift these(More)
Real-world planning problems can require search over thousands of actions and may yield a multitude of plans of differing quality. To solve such real-world planning problems, we need to exploit domain control knowledge that will prune the search space to a manageable size. And to ensure that the plans we generate are of high quality, we need to guide search(More)