Dave Beckett's blog

RDF, OWL and XML syntaxes

2003-02-25 11:58

I'm so tired of seeing morons confuse RDF, OWL and XML syntaxes so I'll record this rather than send it as email to the latest fool.

RDF has an abstract syntax which is triples and very simple:

6 Abstract Syntax (Normative)

This section defines the RDF abstract syntax. The RDF abstract syntax is a set of triples, called the RDF graph.

Resource Description Framework (RDF): Concepts and Abstract Syntax, W3C Working Draft, 23 January 2003

It also has a transfer syntax called RDF/XML which is an XML format that is described in RDF/XML Syntax Specification (Revised), W3C Working Draft, 23 January 2003

OWL has an abstract syntax represented in the RDF syntax (triples) and uses the same transfer syntax as RDF, RDF/XML:

1.1 Purpose of this document

This document gives a systematic, compact and informal description of all the modelling primitives of OWL, using the RDF/XML exchange syntax for OWL.

Web Ontology Language (OWL) Reference Version 1.0, W3C Working Draft 21 February 2003

1.3 OWL syntax

An OWL ontology is represented as a set of RDF triples. As with any set of RDF triples, OWL triples can be represented in many different syntactic forms (as described in the RDF/XML Syntax Specification (Revised) [RDF/XML Syntax]).

Web Ontology Language (OWL) Reference Version 1.0, W3C Working Draft 21 February 2003

There is also something that might be called the "XML encoding of OWL" which is an ambiguous term but usually refers to the informative and not recommended XML encoding sometimes refered to as a "presentation syntax" in one of the OWL drafts. I can't actually find a reference to it just now.