SPARQL is a schema query language allowing access to the TBox part of a knowledge base. Moreover its entailment regimes enable to take into account knowledge inferred from persistently stored knowledge bases in the query answering process. Thus, the emergence of SPARQL entailment regimes provide a new perspective for the containment problem. As one has to deal with axiomatic triples, datatype reasoning, and blank nodes that result in infinite answers. Of particular interest for us is the union of conjunctive queries that are a core fragment of SPARQL. In this paper, we study the containment of such queries based on the OWL-ALCH Direct and RDF-Based Semantics entailment regimes.
