Unique identifier defined for OWL Entailment with RDF-Based Semantics.

“http://www.w3.org/ns/entailment/OWL-RDF-Based” is the URI. The specification for the entailment is part of the OWL 2 W3C Recommendation.

For more information about OWL, please refer to the the OWL 2 Document Overview Recommendation.