Semantic Web Rule Language (SWRL) extends the set of OWL axioms to include Horn-like rules. It thus enables Horn-like rules to be combined with an OWL knowledge base. A high-level abstract syntax is provided that extends the OWL abstract syntax described in the OWL Semantics and Abstract Syntax document [OWL S&AS]. An extension of the OWL model theoretic semantics is also given to provide a formal meaning for OWL ontologies including rules written in this abstract syntax.
