Temporal Reasoning for Supporting Temporal Queries in OWL 2.0

We propose an approach for reasoning and querying over temporal information in OWL ontologies. Representing both qualitative temporal (i.e., information whose temporal extents are unknown such as "before", "after" for temporal relations) in addition to quantitative information (i.e., where temporal information is defined precisely e. g., using dates) is a distinctive feature of the proposed ontology. Qualitative representations are very common in natural language expressions such as in free text or speech and can be proven to be valuable in the Semantic Web. Reasoning rules applying over temporal relations, infer implied relations, detect inconsistencies and retain soundness, completeness and tractability over the supported sets of relations using path consistency. Temporal representations are defined on time instants rather than on intervals (as it is typical in the literature), resulting into simpler yet equivalent representations. A SPARQL-based temporal query language capable of exploiting the characteristics of the underlying representation is also implemented and discussed.