OWL 2 Web Ontology Language
Quick Reference Guide (Second Edition)
W3C Recommendation 11 December 2012
- This version:
- http://www.w3.org/TR/2012/REC-owl2-quick-reference-20121211/
- Latest version (series 2):
- http://www.w3.org/TR/owl2-quick-reference/
- Latest Recommendation:
- http://www.w3.org/TR/owl-quick-reference
- Previous version:
- http://www.w3.org/TR/2012/PER-owl2-quick-reference-20121018/
- Editors:
- Jie Bao, formerly at Rensselaer Polytechnic Institute
- Elisa F. Kendall, Sandpiper Software, Inc.
- Deborah L. McGuinness, Rensselaer Polytechnic Institute
- Peter F. Patel-Schneider, Nuance Communications
- Contributors:
- Li Ding, formerly at Rensselaer Polytechnic Institute
- Ankesh Khandelwal, Rensselaer Polytechnic Institute
Please refer to the errata for this document, which may include some normative corrections.
A color-coded version of this document showing changes made since the previous version is also available.
This document is also available in these non-normative formats: PDF version, Reference Card.
See also translations.
Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.
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.
This document provides a non-normative quick reference guide to the OWL 2 language. It also provides links to other documents, including the OWL 2 Primer for language introduction and examples, the OWL 2 Structural Specification and Functional Syntax document for more details of the functional syntax, and the OWL 2 New Features and Rationale document for new feature descriptions.
May Be Superseded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/.
Summary of Changes
Please Send Comments
Please send any comments to [email protected] (public archive). Although work on this document by the OWL Working Group is complete, comments may be addressed in the errata or in future revisions. Open discussion among developers is welcome at [email protected] (public archive).
Endorsed By W3C
This document has been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and is endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited from another document. W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web.
Patents
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. This document is informative only. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent.
1 Names, Prefixes, and Notation
Names in OWL 2 are IRIs, often written in a shorthand prefix:localname, where prefix: is a prefix name that expands to an IRI, and localname is the remainder of the name. The standard prefix names in OWL 2 are:
| Prefix Name | Expansion |
|---|
| rdf: | http://www.w3.org/1999/02/22-rdf-syntax-ns# |
| rdfs: | http://www.w3.org/2000/01/rdf-schema# |
| owl: | http://www.w3.org/2002/07/owl# |
| xsd: | http://www.w3.org/2001/XMLSchema# |
We use notation conventions in the following tables*:
| Letters | Meaning | Letters | Meaning | Letters | Meaning | Letters | Meaning |
|---|
| C | class expression | CN | class name | D | data range | DN | datatype name |
| P | object property expression | PN | object property name | R | data property | A | annotation property |
| a | individual | aN | individual name | _:a | anonymous individual (a blank node label) | v | literal |
| n | non-negative integer** | f | facet | ON | ontology name | U | IRI |
| s | IRI or anonymous individual | t | IRI, anonymous individual, or literal | p | prefix name | _:x | blank node |
| (a1 … an) | RDF list | | | | | | |
* All of the above can have subscripts. ** as a shorthand for "n"^^xsd:nonNegativeInteger
2 OWL 2 constructs and axioms
For an OWL 2 DL ontology, there are some global restrictions on axioms.
In the following tables the first column provides links to the Primer (if applicable), the second column provides links to the Functional Syntax, and the third column gives RDF triples in the Turtle syntax.
Predefined and Named Classes
| Language Feature | Functional Syntax | RDF Syntax |
|---|
| named class | CN | CN |
| universal class | owl:Thing | owl:Thing |
| empty class | owl:Nothing | owl:Nothing |
Boolean Connectives and Enumeration of Individuals
Object Property Restrictions
Data Property Restrictions
| Language Feature | Functional Syntax | RDF Syntax |
|---|
| universal | DataAllValuesFrom(R D) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:allValuesFrom D. |
| existential | DataSomeValuesFrom(R D) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:someValuesFrom D. |
| literal value | DataHasValue(R v) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:hasValue v. |
| exact cardinality | DataExactCardinality(n R) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:cardinality n. |
| qualified exact cardinality | DataExactCardinality(n R D) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:qualifiedCardinality n.
_:x owl:onDataRange D. |
| maximum cardinality | DataMaxCardinality(n R) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:maxCardinality n. |
| qualified maximum cardinality | DataMaxCardinality(n R D) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:maxQualifiedCardinality n.
_:x owl:onDataRange D. |
| minimum cardinality | DataMinCardinality(n R) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:minCardinality n. |
| qualified minimum cardinality | DataMinCardinality(n R D) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:minQualifiedCardinality n.
_:x owl:onDataRange D. |
Restrictions Using n-ary Data Range
In the following table 'Dn' is an n-ary data range.
| Language Feature | Functional Syntax | RDF Syntax |
|---|
| n-ary universal | DataAllValuesFrom(R1 … Rn Dn) | _:x rdf:type owl:Restriction.
_:x owl:onProperties ( R1 … Rn ).
_:x owl:allValuesFrom Dn. |
| n-ary existential | DataSomeValuesFrom(R1 … Rn Dn) | _:x rdf:type owl:Restriction.
_:x owl:onProperties ( R1 … Rn).
_:x owl:someValuesFrom Dn. |
2.2 Properties
Object Property Expressions
Data Property Expressions
2.3 Individuals & Literals
2.4 Data Ranges
Data Range Expressions
2.5 Axioms
Class Expression Axioms
Object Property Axioms
Data Property Axioms
Datatype Definitions
Assertions
Keys
| Language Feature | Functional Syntax | RDF Syntax |
|---|
| Key | HasKey(C (P1 … Pm) (R1 … Rn) ) | C owl:hasKey (P1 … Pm R1 … Rn).
m+n>0 |
2.6 Declarations
2.7 Annotations
Annotations
Annotation Properties
Annotation Axioms
2.8 Ontologies
Ontologies
| Language Feature | Functional Syntax | RDF Syntax |
|---|
OWL ontology
(importing)1 2 |
Ontology([ON [U]]
Import(ON1)...
Annotation(A t)
...
) | ON rdf:type owl:Ontology.
[ON owl:versionIRI U.]
ON owl:imports ON1. ...
ON A t.
... |
| prefix declaration3 | Prefix(p=U) | @prefix p U. |
- [ ] represents optional constructs
- In the RDF syntax _:x is used in place of ON if there is no ontology name.
- RDF syntax is in Turtle, other RDF serializations may vary.
3 Built-in Datatypes and Facets
3.1 Built-in Datatypes
3.2 Facets
| Facet | Value | Applicable Datatypes | Explanation |
|---|
xsd:minInclusive
xsd:maxInclusive
xsd:minExclusive
xsd:maxExclusive | literal in the corresponding datatype | Numbers,
Time Instants | Restricts the value-space to greater than (equal to) or lesser than (equal to) a value |
xsd:minLength
xsd:maxLength
xsd:length | Non-negative integer | Strings,
Binary Data,
IRIs | Restricts the value-space based on the
lengths of the literals |
| xsd:pattern | xsd:string literal as a regular expression | Strings,
IRIs | Restricts the value space to literals that> match the regular expression |
| rdf:langRange | xsd:string literal as a regular expression | rdf:PlainLiteral | Restricts the value space to literals with language tags that match the regular expression |
4 Appendix
4.1 New Features in OWL 2
| Class Expressions | |
| Class Axioms | |
| Property Expressions | |
| Property Axioms | |
| Data Ranges | |
| Assertions | |
| Annotation | |
| Extra Built-in Datatypes | - owl:rational, owl:real, xsd:dateTimeStamp, rdf:PlainLiteral
|
| Others | |
4.2 Additional Vocabulary in OWL 2 RDF Syntax
| Feature | Vocabulary | Note |
|---|
| data range | owl:DataRange | deprecated in OWL 2, replaced by rdfs:Datatype |
| membership of a set of pairwise different individuals | owl:distinctMembers | can alternatively use owl:members |
| ontology property | owl:OntologyProperty | |
| deprecation | owl:DeprecatedClass,
owl:DeprecatedProperty | alternative RDF syntax:
s rdf:type owl:DeprecatedClass . or
s rdf:type owl:DeprecatedProperty .
can be replaced by
s owl:deprecated "true"^^xsd:boolean . |
5 Appendix: Change Log (Informative)
5.1 Changes Since Recommendation
This section summarizes the changes to this document since the Recommendation of 27 October, 2009.
- With the publication of the XML Schema Definition Language (XSD) 1.1 Part 2: Datatypes Recommendation of 5 April 2012, the elements of OWL 2 which are based on XSD 1.1 are now considered required, and the note detailing the optional dependency on the XSD 1.1 Candidate Recommendation of 30 April, 2009 has been removed from the "Status of this Document" section.
- Minor typographical errors were corrected as detailed on the OWL 2 Errata page.
5.2 Changes Since Proposed Recommendation
This section summarizes the changes to this document since the Proposed Recommendation of 22 September, 2009.
- Minor editorial changes to "Annotations" table.
- Minor editorial change to the explanation of table headers and others.
- Link to a pdf version of the guide, i.e., the OWL 2 Reference Card.
5.3 Changes Since Candidate Recommendation
This section summarizes the changes to this document since the Candidate Recommendation of 11 June, 2009.
- The "Features At Risk" note w.r.t. the owl:rational and rdf:XMLLiteral datatypes was removed: implementation support has been adequately demonstrated, and the features are no longer considered at risk (see Resolution 5 and Resolution 6, 05 August 2009).
- Some minor editorial changes were made.
6 Acknowledgments
The starting point for the development of OWL 2 was the OWL1.1 member submission, itself a result of user and developer feedback, and in particular of information gathered during the OWL Experiences and Directions (OWLED) Workshop series. The working group also considered postponed issues from the WebOnt Working Group.
This document has been produced by the OWL Working Group (see below), and its contents reflect extensive discussions within the Working Group as a whole. The editors extend special thanks to Bernardo Cuenca Grau (Oxford University), Christine Golbreich (Université de Versailles St-Quentin and LIRMM), Ivan Herman (W3C/ERCIM), and Bijan Parsia (University of Manchester) for their thorough reviews.
The regular attendees at meetings of the OWL Working Group at the time of publication of this document were: Jie Bao (RPI), Diego Calvanese (Free University of Bozen-Bolzano), Bernardo Cuenca Grau (Oxford University Computing Laboratory), Martin Dzbor (Open University), Achille Fokoue (IBM Corporation), Christine Golbreich (Université de Versailles St-Quentin and LIRMM), Sandro Hawke (W3C/MIT), Ivan Herman (W3C/ERCIM), Rinke Hoekstra (University of Amsterdam), Ian Horrocks (Oxford University Computing Laboratory), Elisa Kendall (Sandpiper Software), Markus Krötzsch (FZI), Carsten Lutz (Universität Bremen), Deborah L. McGuinness (RPI), Boris Motik (Oxford University Computing Laboratory), Jeff Pan (University of Aberdeen), Bijan Parsia (University of Manchester), Peter F. Patel-Schneider (Bell Labs Research, Alcatel-Lucent), Sebastian Rudolph (FZI), Alan Ruttenberg (Science Commons), Uli Sattler (University of Manchester), Michael Schneider (FZI), Mike Smith (Clark & Parsia), Evan Wallace (NIST), Zhe Wu (Oracle Corporation), and Antoine Zimmermann (DERI Galway). We would also like to thank past members of the working group: Jeremy Carroll, Jim Hendler, and Vipul Kashyap.