23 citations · 29 across the 8 of their papers we have counts for
9 papers
Characterising Fixed Parameter Tractability of Query Evaluation over Guarded TGDs
Cristina Feier
We study the parameterized complexity of evaluating Ontology Mediated Queries (OMQs) based on Guarded TGDs (GTGDs) and Unions of Conjunctive Queries (UCQs), in the case where relat…
Answer Counting under Guarded TGDs
Cristina Feier, Carsten Lutz, Marcin Przybyłko
We study the complexity of answer counting for ontology-mediated queries and for querying under constraints, considering conjunctive queries and unions thereof (UCQs) as the query…
From Conjunctive Queries to Instance Queries in Ontology-Mediated Querying
Cristina Feier, Carsten Lutz, Frank Wolter
We consider ontology-mediated queries (OMQs) based on expressive description logics of the ALC family and (unions) of conjunctive queries, studying the rewritability into OMQs base…
When is Ontology-Mediated Querying Efficient?
Pablo Barcelo, Cristina Feier, Carsten Lutz +1
In ontology-mediated querying, description logic (DL) ontologies are used to enrich incomplete data with domain knowledge which results in more complete answers to queries. However…
The Limits of Efficiency for Open- and Closed-World Query Evaluation Under Guarded TGDs
Pablo Barcelo, Victor Dalmau, Cristina Feier +2
Ontology-mediated querying and querying in the presence of constraints are two key database problems where tuple-generating dependencies (TGDs) play a central role. In ontology-med…
A Practical Acyclicity Notion for Query Answering over Horn-SRIQ Ontologies
David Carral, Cristina Feier, Pascal Hitzler
Conjunctive query answering over expressive Horn Description Logic ontologies is a relevant and challenging problem which, in some cases, can be addressed by application of the cha…