OWL 2 Web Ontology Language
Quick Reference Guide
W3C Editor's Draft 16 April 2009
- This version:
- http://www.w3.org/2007/OWL/draft/ED-owl2-quick-reference-20090416/
- Latest editor's draft:
- http://www.w3.org/2007/OWL/draft/owl2-quick-reference/
- Authors:
- Jie Bao, Rensselaer Polytechnic Institute
- Elisa F. Kendall, Sandpiper Software, Inc.
- Deborah L. McGuinness, Rensselaer Polytechnic Institute
- Contributors:
- Li Ding, Rensselaer Polytechnic Institute
- Ankesh Khandelwal, Rensselaer Polytechnic Institute
- Peter F. Patel-Schneider, Bell Labs Research, Alcatel-Lucent
This document is also available in these non-normative formats: PDF version.
Copyright © 2009 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.
his document provides a quick reference guide to the OWL 2 language, similar to what was provided in the
Language Synopsis section of the
OWL Web Ontology Language Overview. Inspiration for this effort includes work by the
ebiquity Research Group at the
University of Maryland Baltimore County (UMBC) on earlier versions of a
Reference Card for the Semantic Web.
A draft
printable version is available , but it is obsolete with respect to the current wiki version.
May Be Superseded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
This Working Draft has numerous editorial changes since the
previous version of 02 December 2008. In particular, the
presentation has been significantly improved, and the content has
been updated to reflect changes in the language specification.
Please Comment By 7 May 2009
The OWL Working Groupseeks
public feedback on this Working Draft. Please send your
comments to public-owl-comments@w3.org (public archive). If possible, please offer
specific changes to the text that would address your
concern. You may also wish to check the Wiki
Version of this document and see if the relevant text has already
been updated.
No Endorsement
Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
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. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
Editor's Note: To do list:
Editor's Note: Markup suggestions from Ivan Herman
- the gray background shading is a little bit disturbing, maybe try other typographic trick, e.g., some lighter colour.
- whether we could find a trick so that we can switch on/off highlight the OWL 1/2 differences and the '?' links that refer to the NF&R.
1 Namespaces
The standard namespaces and prefixes in OWL 2 are
2 OWL 2 constructs and axioms
Features in bold are only available in OWL 2. Each table has columns:
We use the following notation conventions: unless stated otherwise, "C" is an OWL class, "D" is a data range, "P" and "Q" are object properties, "R" and "S" are data properties, "a" is an OWL individual, "u" and "v" are literals, "n" is a non-negative integer, "_:x" is anonymous individual. All names may have subscripts. "(a1 … an)" in the 3rd column stands for a rdf list.
Editor's Note: Christine suggested to use same naming convention as in Syntax, e.g., CE, DR, OPE, DPE, a and lt
For an OWL 2 DL ontology, there are some global restrictions on axioms.
- Predefined Classes
| all OWL individuals | owl:Thing | owl:Thing
|
| empty class | owl:Nothing | owl:Nothing
|
- Boolean Connectives and Enumeration of Individuals
- Object Property Restrictions
- Every owl:Restriction is an owl:Class.
- Data Property Restrictions
- Every owl:Restriction is an owl:Class.
| 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.
|
| individual value | DataHasValue(R u) | _:x rdf:type owl:Restriction.
_:x owl:onProperty R.
_:x owl:hasValue u.
|
| exact cardinality | DataExactCardinality(n R)
DataExactCardinality(n R D) (N)
| _:x rdf:type owl:Restriction.
_:x owl:onProperty P.
_:x owl:cardinality "n"^^xsd:nonNegativeInteger.
_:x owl:qualifiedCardinality "n"^^xsd:nonNegativeInteger. (without D)
_:x owl:onDataRange D. (with D)
|
| maximum cardinality | DataMaxCardinality(n R)
DataMaxCardinality(n R D) (N) | _:x rdf:type owl:Restriction.
_:x owl:onProperty P.
_:x owl:maxCardinality "n"^^xsd:nonNegativeInteger. (without D)
_:x owl:maxQualifiedCardinality "n"^^xsd:nonNegativeInteger.
_:x owl:onDataRange D. (with D)
|
| minimum cardinality | DataMinCardinality(n R)
DataMinCardinality(n R D) (N) | _:x rdf:type owl:Restriction.
_:x owl:onProperty P.(without D)
_:x owl:minCardinality "n"^^xsd:nonNegativeInteger.
_:x owl:minQualifiedCardinality "n"^^xsd:nonNegativeInteger.
_:x owl:onDataRange D. (with D)
|
- Restrictions Using n-ary Data Range
- "Dn" is a n-ary data range (cf #Data Ranges).
| n-ary universal (N) | DataAllValuesFrom(R1 … Rn Dn) | _:x rdf:type owl:Restriction.
_:x owl:onProperties ( R1 … Rn ).
_:x owl:allValuesFrom Dn.
|
| n-ary existential (N) | DataSomeValuesFrom(R1 … Rn Dn) | _:x rdf:type owl:Restriction.
_:x owl:onProperties ( R1 … Rn).
_:x owl:someValuesFrom Dn.
|
2.1.1 Class Axioms
2.2 Properties
2.2.1 Property Expressions
- Datatype Properties are instances of owl:DatatypeProperty
2.2.2 Property Axioms
2.3 Data Ranges
- Built-in datatypes are unary data ranges. OWL 2 does not provide direct support for n-ary data ranges but provides syntactical hooks for applications to add them.
2.4 Keys
| Keys (N) | HasKey(C (P1 … Pm) (R1 … Rn) ) | C owl:hasKey (P1 … Pm R1 … Rn).
|
2.5 Assertions
2.6 Declarations
| class (N) | Declaration( Class( C ) ) | C rdf:type owl:Class.
|
| datatype (N) | Declaration( Datatype( D ) ) | D rdf:type rdfs:Datatype.
|
| object property (N) | Declaration( ObjectProperty( P ) ) | P rdf:type owl:ObjectProperty.
|
| datatype property (N) | Declaration( DataProperty( R ) ) | R rdf:type owl:DatatypeProperty.
|
| annotation property (N) | Declaration( AnnotationProperty( A ) ) | A rdf:type owl:AnnotationProperty.
|
| named individual (N) | Declaration( NamedIndividual( a ) ) | a rdf:type owl:NamedIndividual.
|
2.7 Annotations
- Annotation of an object
- s the annotation subject, v a resource; AP annotation property.
- Note: an annotated object can be an ontology, an ontology entity, an anonymous individual, or another annotation.
- Annotation of an axiom
- y the annotated object, AP annotation property, v a resource
| axiom annotations (N) | AXIOM(Annotation( AP v) ) | s p o.
_:x rdf:type owl:Axiom.
_:x owl:subject s.
_:x owl:predicate p.
_:x owl:object o.
_:x AP v.
If AXIOM(...) becomes s p o.
_:x p o
_:x AP v.
If AXIOM(...) becomes _:x p o.
|
- Note: for n-ary axioms of type EquivalentClasses, EquivalentProperties or SameIndividual, they will first be broken up into several RDF triples of their binary forms, then each triple is reified using the above rule.
- Annotation Properties
- all annotation properties are instances of owl:AnnotationProperty
- Annotation Axioms
- AP annotation property, U an IRI.
- Deprecation
- C an OWL class or a datatype, P an object property, datatype property or annotation property.
| deprecated class | C Deprecated | C rdf:type owl:DeprecatedClass.
|
| deprecated property | P Deprecated | P rdf:type owl:DeprecatedProperty.
|
- Note: "Deprecated" is the short for owl:deprecated "true"^^xsd:boolean
2.8 OWL Ontologies
- Annotations of Ontologies
- O an ontology, U an ontology IRI, V an IRI.
- Note: if O is unnamed, then O is mapped to _:x (an anonymous individual).
- Ontology Properties are instances of owl:OntologyProperty
| backwards compatibility | O owl:backwardCompatibleWith U.
|
| incompatibility | O owl:incompatibleWith U.
|
| prior version | O owl:priorVersion U.
|
2.9 Deprecated Vocabulary in OWL 2
| owl:DataRange | replaced by rdfs:Datatype
|
| owl:distinctMembers | replaced by owl:members
|
3 Built-in Datatypes and Facets
3.1 Built-in Datatypes
- The value space is a set determining the set of values of the datatype. A literal value "abc" of the datatype DT can be given in the form "abc"^^DT.
- OWL Numeric Datetypes:
| owl:rational (rational numbers)
|
| owl:real (N)(real numbers)
|
- XSD Numeric Datatypes
| xsd:double | xsd:nonNegativeInteger | xsd:long | xsd:unsignedLong
|
| xsd:float | xsd:nonPositiveInteger | xsd:int | xsd:unsignedInt
|
| xsd:decimal | xsd:positiveInteger | xsd:short | xsd:unsignedShort
|
| xsd:integer | xsd:negativeInteger | xsd:byte | xsd:unsignedByte
|
- Strings: value space is of the form <"abc", tag>
- Strings with a Language Tag: tag is either an empty string or a lowercase language tag
- Strings without a Language Tag: tag is an empty string
| xsd:string | xsd:NCName | xsd:normalizedString | xsd:NMTOKEN
|
| xsd:token | xsd:language | xsd:Name
|
| xsd:Boolean (value space has only two values: true and false)
|
| xsd:base64Binary | xsd:hexBinary
|
| xsd:anyURI | IRIs as defined in XML Schema Datatypes
|
| xsd:dateTime | time instants with time zone offset
|
| xsd:dateTimeStamp | time instants without time zone offset
|
| rdf:XMLLiteral | Note: at risk in OWL 2
|
3.2 Facets
The facet space is a set of pairs of the form < f v >, where f is an IRI called a constraining facet, and v is a value. Each such pair is mapped to a subset of the value space of the datatype.
Notations: Numeric Datatype, String Datatype and Binary datatype refer to a set of datatypes based on the classification done in the prior section.
| Facet(N) f | Datatype | Value v | Explanation
|
xsd:minInclusive,
xsd:maxInclusive,
xsd:minExclusive,
xsd:maxExclusive
| Numeric Datatype DT,
Time instant DT
| Literal in DT
| Restricts the value-space to greater than (equal to)
or lesser than (equal to) a value
|
xsd:minLength,
xsd:maxLength,
xsd:length
| String Datatype,
Binary Datatype,
xsd:anyURI
| Nonnegative integer
| Restricts the value-space based on the
lengths of the literals
|
| xsd:pattern
| String Datatype,
xsd:anyURI
| xsd:string literal whose value is a regular expression
| Restricts the value space to literals that
match the regular expression
|
| rdf:langRange
| rdf:text
| xsd:string literal whose value is a regular expression
| Restricts the value space to literals with
language tags that match the regular expression
|
4 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),
Bijan Parsia (University of Manchester) and
Peter F. Patel-Schneider (Bell Labs Research, Alcatel-Lucent)
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),
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),
Elisa Kendall (Sandpiper Software),
Markus Krötzsch (FZI),
Carsten Lutz (Universität Bremen),
Deborah L. McGuinness (RPI),
Boris Motik (Oxford University),
Jeff Pan (University of Aberdeen),
Bijan Parsia (University of Manchester),
Peter F. Patel-Schneider (Bell Labs Research, Alcatel-Lucent),
Alan Ruttenberg (Science Commons),
Uli Sattler (University of Manchester),
Michael Schneider (FZI),
Mike Smith (Clark & Parsia),
Evan Wallace (NIST), and
Zhe Wu (Oracle Corporation).
We would also like to thank past members of the working group:
Jeremy Carroll,
Jim Hendler,
Vipul Kashyap.