OWL 2 Web Ontology Language
Structural Specification and Functional-Style
Syntax
W3C Recommendation 27 October 2009
This version:
http://www.w3.org/TR/2009/REC-owl2-syntax-20091027/
Latest version (series 2):
http://www.w3.org/TR/owl2-syntax/
Latest Recommendation:
http://www.w3.org/TR/owl-syntax
Previous version:
http://www.w3.org/TR/2009/PR-owl2-syntax-20090922/ (color-coded diff)
Editors:
Boris Motik, Oxford University Computing Laboratory
Peter F. Patel-Schneider, Bell Labs Research, Alcatel-Lucent
Bijan Parsia, University of Manchester
Contributors: (in alphabetical order)
Conrad Bock, National Institute of Standards and Technology (NIST)
Achille Fokoue, IBM Corporation
Peter Haase, FZI Research Center for Information Technology
Rinke Hoekstra, University of Amsterdam
Ian Horrocks, Oxford University Computing Laboratory
Alan Ruttenberg, Science Commons (Creative Commons)
Uli Sattler, University of Manchester
Michael Smith, Clark & Parsia
Please refer to the errata for this document, which may include some normative
corrections.
This document is also available in these non-normative formats: PDF version.
See also translations.
Copyright © 2009 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability,
trademark and document use rules apply.
OWL 2 Web Ontology Language Structural Specification and
Functional-Style Syntax
W3C Recommendation 27
October 2009
Page 1 of 134 http://www.w3.org/TR/2009/REC-owl2-syntax-20091027/

Abstract
The OWL 2 Web Ontology Language, informally OWL 2, is an ontology language
for the Semantic Web with formally defined meaning. OWL 2 ontologies provide
classes, properties, individuals, and data values and are stored as Semantic Web
documents. OWL 2 ontologies can be used along with information written in RDF,
and OWL 2 ontologies themselves are primarily exchanged as RDF documents.
The OWL 2 Document Overview describes the overall state of OWL 2, and should
be read before other OWL 2 documents.
The meaningful constructs provided by OWL 2 are defined in terms of their
structure. As well, a functional-style syntax is defined for these constructs, with
examples and informal descriptions. One can reason with OWL 2 ontologies under
either the RDF-Based Semantics [OWL 2 RDF-Based Semantics] or the Direct
Semantics [OWL 2 Direct Semantics]. If certain restrictions on OWL 2 ontologies
are satisfied and the ontology is in OWL 2 DL, reasoning under the Direct
Semantics can be implemented using techniques well known in the literature.
Status of this Document
May Be Superseded
This section describes the status of this document at the time of its publication.
Other documents may supersede this document. A list of current W3C publications
and the latest revision of this technical report can be found in the W3C technical
reports index at http://www.w3.org/TR/.
XML Schema Datatypes Dependency
OWL 2 is defined to use datatypes defined in the XML Schema Definition
Language (XSD). As of this writing, the latest W3C Recommendation for XSD is
version 1.0, with version 1.1 progressing toward Recommendation. OWL 2 has
been designed to take advantage of the new datatypes and clearer explanations
available in XSD 1.1, but for now those advantages are being partially put on hold.
Specifically, until XSD 1.1 becomes a W3C Recommendation, the elements of
OWL 2 which are based on it should be considered optional, as detailed in
Conformance, section 2.3. Upon the publication of XSD 1.1 as a W3C
Recommendation, those elements cease to be optional and are to be considered
required as otherwise specified.
We suggest that for now developers and users follow the XSD 1.1 Candidate
Recommendation. Based on discussions between the Schema and OWL Working
Groups, we do not expect any implementation changes will be necessary as XSD
1.1 advances to Recommendation.
OWL 2 Web Ontology Language Structural Specification and
Functional-Style Syntax
W3C Recommendation 27
October 2009
Page 2 of 134 http://www.w3.org/TR/2009/REC-owl2-syntax-20091027/