This appendix provides a brief introduction to RDF [12,18] and OWL [19,31], the primary modelling formalisms used in Semantic Web applications. The essential structure of RDF graphs is presented, followed by discussions of the concrete RDF syntax Turtle, RDFS, and the semantics of RDF. OWL, its semantics, and tractable OWL profiles are then presented.

Though they were both specifically developed for the Semantic Web and their development occurred in tandem, the motivations underlying RDF and OWL are different, and this is reflected in the syntax and semantics of each. RDF is intended to be simple and open, allowing users on the Web to make statements about resources. From the standpoint of logical expressivity, it is relatively limited. OWL, in contrast, is intended explicitly for the development of formal ontologies, and as such it has a more sophisticated logical syntax and semantics.

Both RDF and OWL are developed and maintained by the World Wide Web Consortium (W3C)

https://www.w3.org/