2 results
Carsten Lutz ; Frank Wolter.
We analyze the data complexity of ontology-mediated querying where the ontologies are formulated in a description logic (DL) of the ALC family and queries are conjunctive queries, positive existential queries, or acyclic conjunctive queries. Our approach is non-uniform in the sense that we aim to […]
Published on November 13, 2017
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 language and guarded TGDs as the ontology and constraint language, respectively. Our main result is a classification […]
Published on September 14, 2023