This document provides a quick reference guide for OWL 2 Web Ontology Language. It defines common prefixes used in OWL, such as owl:, rdf:, rdfs:, and xsd:. It also defines notation for OWL components like classes, properties, individuals, and data ranges. Tables are provided describing syntax for object property expressions, data property expressions, individuals and literals, and data range expressions.

1. OWL 2 Web Ontology Language individual value ObjectHasValue
(P a)
_:x rdf:type owl:Restriction.
_:x owl:onProperty P.
2.2 Properties
Quick Reference Guide _:x owl:hasValue a.
Object Property Expressions
local reflexivity ObjectHasSelf _:x rdf:type owl:Restriction. named object property PN PN
http://www.w3.org/2007/OWL/refcard (P) _:x owl:onProperty P. universal object property owl:topObjectProperty owl:topObjectProperty
_:x owl:hasSelf "true"^^xsd:boolean. empty object property owl:bottomObjectProperty owl:bottomObjectProperty
1 Names, Prefixes, and Notation exact cardinality ObjectExactCardinality _:x rdf:type owl:Restriction. inverse property ObjectInverseOf(PN) _:x owl:inverseOf PN
(n P) _:x owl:onProperty P.
Names in OWL 2 are IRIs, often written in a shorthand prefix:localname, where prefix: is _:x owl:cardinality n. Data Property Expressions
a prefix name that expands to an IRI, and localname is the remainder of the name. qualified exact ObjectExactCardinality _:x rdf:type owl:Restriction.
The prefix names in OWL 2 are: cardinality (n P C) _:x owl:onProperty P. named data property R R
_:x owl:qualifiedCardinality n. universal data property owl:topDataProperty owl:topDataProperty
Prefix Name Expansion _:x owl:onClass C. empty data property owl:bottomDataProperty owl:bottomDataProperty
rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns# maximum ObjectMaxCardinality _:x rdf:type owl:Restriction.
rdfs: http://www.w3.org/2000/01/rdf-schema# cardinality (n P) _:x owl:onProperty P. 2.3 Individuals & Literals
owl: http://www.w3.org/2002/07/owl# _:x owl:maxCardinality n.
xsd: http://www.w3.org/2001/XMLSchema# qualified ObjectMaxCardinality _:x rdf:type owl:Restriction. named individual aN aN
maximum (n P C) _:x owl:onProperty P. anonymous individual _:a _:a
cardinality _:x owl:maxQualifiedCardinality n. literal (datatype value) "abc"^^DN "abc"^^DN
We use notation conventions in the following tables*:
Letters Meaning Letters Meaning _:x owl:onClass C.
(a1 … an) RDF list n non-negative integer** minimum ObjectMinCardinality _:x rdf:type owl:Restriction. 2.4 Data Ranges
_:a anonymous individual ON ontology name cardinality (n P) _:x owl:onProperty P.
(a blank node label) _:x owl:minCardinality n. Data Range Expressions
_:x blank node P object property expression qualified ObjectMinCardinality _:x rdf:type owl:Restriction.
minimum (n P C) _:x owl:onProperty P. named datatype DN DN
a individual p prefix name data range DataComplementOf _:x rdf:type rdfs:Datatype.
A annotation property PN object property name cardinality _:x owl:minQualifiedCardinality n.
_:x owl:onClass C. complement (D) _:x owl:datatypeComplementOf D.
aN individual name R data property data range DataIntersectionOf _:x rdf:type rdfs:Datatype.
C class expression s IRI or anonymous individual Data Property Restrictions intersection (D1…Dn) _:x owl:intersectionOf (D1…Dn).
CN class name t IRI, anonymous individual, or data range union DataUnionOf _:x rdf:type rdfs:Datatype.
literal universal DataAllValuesFrom _:x rdf:type owl:Restriction.
(R D) _:x owl:onProperty R. (D1…Dn) _:x owl:unionOf (D1…Dn).
D data range U IRI literal DataOneOf _:x rdf:type rdfs:Datatype.
DN datatype name v literal _:x owl:allValuesFrom D.
existential DataSomeValuesFrom _:x rdf:type owl:Restriction. enumeration (v1 … vn) _:x owl:oneOf ( v1 … vn ).
f facet datatype DatatypeRestriction _:x rdf:type rdfs:Datatype.
* All of the above can have subscripts. (R D) _:x owl:onProperty R.
_:x owl:someValuesFrom D. restriction (DN f1 v1 … fn vn) _:x owl:onDatatype DN.
** As a shorthand for "n"^^xsd:nonNegativeInteger _:x owl:withRestrictions (_:x1 ... _:xn).
literal value DataHasValue _:x rdf:type owl:Restriction.
_:xj fj vj. j=1…n
2 OWL 2 constructs and axioms (R v) _:x owl:onProperty R.
_:x owl:hasValue v.
In the following tables, the three columns are: exact cardinality DataExactCardinality _:x rdf:type owl:Restriction. 2.5 Axioms
Language Feature Functional Syntax RDF Syntax (Turtle) (n R) _:x owl:onProperty R.
_:x owl:cardinality n. Class Expression Axioms
For an OWL 2 DL ontology, there are additional global restrictions on axioms. qualified exact DataExactCardinality _:x rdf:type owl:Restriction.
subclass SubClassOf(C1 C2) C1 rdfs:subClassOf C2.
2.1 Class Expressions cardinality (n R D) _:x owl:onProperty R.
equivalent classes EquivalentClasses Cj owl:equivalentClass Cj+1.
_:x owl:qualifiedCardinality n.
(C1 … Cn) j=1…n-1
Predefined and Named Classes _:x owl:onDataRange D.
disjoint classes DisjointClasses(C1 C2) C1 owl:disjointWith C2.
maximum DataMaxCardinality _:x rdf:type owl:Restriction.
named class CN CN pairwise disjoint DisjointClasses _:x rdf:type owl:AllDisjointClasses.
cardinality (n R) _:x owl:onProperty R.
universal class owl:Thing owl:Thing classes (C1 … Cn) _:x owl:members ( C1 … Cn ).
_:x owl:maxCardinality n.
empty class owl:Nothing owl:Nothing disjoint union DisjointUnionOf CN owl:disjointUnionOf ( C1… Cn ).
qualified DataMaxCardinality _:x rdf:type owl:Restriction.
(CN C1 … Cn)
Boolean Connectives and Enumeration of Individuals maximum (n R D) _:x owl:onProperty R.
cardinality _:x owl:maxQualifiedCardinality n. Object Property Axioms
intersection ObjectIntersectionOf _:x rdf:type owl:Class. _:x owl:onDataRange D.
(C1…Cn) _:x owl:intersectionOf ( C1…Cn ). minimum DataMinCardinality _:x rdf:type owl:Restriction. subproperty SubObjectPropertyOf P1 rdfs:subPropertyOf P2.
union ObjectUnionOf _:x rdf:type owl:Class. cardinality (n R) _:x owl:onProperty R. (P1 P2)
(C1 … Cn) _:x owl:unionOf ( C1 … Cn ). _:x owl:minCardinality n. property chain SubObjectPropertyOf P owl:propertyChainAxiom
complement ObjectComplementOf _:x rdf:type owl:Class. qualified DataMinCardinality _:x rdf:type owl:Restriction. inclusion (ObjectPropertyChain (P1 … Pn).
(C) _:x owl:complementOf C. minimum (n R D) _:x owl:onProperty R. (P1 … Pn) P)
enumeration ObjectOneOf _:x rdf:type owl:Class. cardinality _:x owl:minQualifiedCardinality n. property domain ObjectPropertyDomain P rdfs:domain C.
(a1 … an) _:x owl:oneOf ( a1 … an ). _:x owl:onDataRange D. (P C)
property range ObjectPropertyRange P rdfs:range C.
Object Property Restrictions Restrictions Using n-ary Data Range
(P C)
universal ObjectAllValuesFrom _:x rdf:type owl:Restriction. In the following table 'Dn' is an n-ary data range. equivalent EquivalentObjectProperties Pj owl:equivalentProperty Pj+1.
(P C) _:x owl:onProperty P. n-ary universal DataAllValuesFrom _:x rdf:type owl:Restriction. properties (P1 … Pn) j=1…n-1
_:x owl:allValuesFrom C (R1 … Rn Dn) _:x owl:onProperties ( R1 … Rn ). disjoint properties DisjointObjectProperties P1 owl:propertyDisjointWith P2.
existential ObjectSomeValuesFrom _:x rdf:type owl:Restriction. _:x owl:allValuesFrom Dn. (P1 P2)
(P C) _:x owl:onProperty P. n-ary DataSomeValuesFrom _:x rdf:type owl:Restriction. pairwise disjoint DisjointObjectProperties _:x rdf:type
_:x owl:someValuesFrom C existential (R1 … Rn Dn) _:x owl:onProperties ( R1 … Rn). properties (P1 … Pn) owl:AllDisjointProperties.
_:x owl:someValuesFrom Dn. _:x owl:members ( P1 … Pn ).

2. inverse InverseObjectProperties P1 owl:inverseOf P2. data property Declaration( DataProperty( R ) ) R rdf:type owl:DatatypeProperty. 3 Built-in Datatypes and Facets
properties (P1 P2) annotation Declaration A rdf:type owl:AnnotationProperty.
functional FunctionalObjectProperty P rdf:type property ( AnnotationProperty( A ) )
property (P) owl:FunctionalProperty. named Declaration aN rdf:type owl:NamedIndividual. 3.1 Built-in Datatypes
inverse InverseFunctionalObjectProperty P rdf:type individual ( NamedIndividual( aN ) )
Universal rdfs:Literal
functional (P) owl:InverseFunctionalProperty.
Datatype
property 2.7 Annotations Numbers owl:rational owl:real
reflexive ReflexiveObjectProperty P rdf:type Annotations xsd:double xsd:float xsd:decimal xsd:integer
property (P) owl:ReflexiveProperty.
annotation assertion AnnotationAssertion s A t. xsd:long xsd:int xsd:short xsd:byte
irreflexive IrreflexiveObjectProperty P rdf:type
(A s t) xsd:nonNegativeInteger xsd:nonPositiveInteger
property (P) owl:IrreflexiveProperty.
annotation of an axiom AXIOM(Annotation _:xi A t. xsd:positiveInteger xsd:negativeInteger
symmetric SymmetricObjectProperty P rdf:type
(where the axiom in RDF (A t) …) si U ti. xsd:unsignedLong xsd:unsignedInt
property (P) owl:SymmetricProperty.
is one or more triples of … xsd:unsignedShort xsd:unsignedByte
asymmetric AsymmetricObjectProperty P rdf:type
the form si U ti, i.e., with _:xi rdf:type owl:Axiom. Strings rdf:PlainLiteral (RDF plain literals)
property (P) owl:AsymmetricProperty.
the same predicate U.) _:xi owl:annotatedSource si. xsd:string xsd:NCName xsd:Name xsd:NMTOKEN
transitive TransitiveObjectProperty P rdf:type
_:xi owl:annotatedProperty U. xsd:token xsd:language xsd:normalizedString
property (P) owl:TransitiveProperty.
_:xi owl:annotatedTarget ti. Boolean Values xsd:boolean (value space: true and false)
Data Property Axioms annotation of an axiom AXIOM(Annotation _:x A t. Binary Data xsd:base64Binary xsd:hexBinary
where the axiom in RDF (A t) … ) _:x U t1. IRIs xsd:anyURI
subproperty SubDataPropertyOf(R1 R2) R1 rdfs:subPropertyOf R2. Time Instants xsd:dateTime (optional time zone offset)
property domain DataPropertyDomain(R C) R rdfs:domain C. is _:x U t1 …
annotation of another Annotation(Annotation _:x A t. xsd:dateTimeStamp (required time zone offset)
property range DataPropertyRange(R D) R rdfs:range D. XML Literals rdf:XMLLiteral
equivalent EquivalentDataProperties Rj owl:equivalentProperty Rj+1. annotation (A t) … A1 t1) s1 A1 t1.
properties (R1 … Rn) j=1…n-1 (the other annotation in …
disjoint properties DisjointDataProperties R1 owl:propertyDisjointWith R2. RDF starts with s1) _:x rdf:type owl:Annotation. 3.2 Facets
(R1 R2) _:x owl:annotatedSource s1.
_:x owl:annotatedProperty A1. Facet Value Applicable Explanation
pairwise disjoint DisjointDataProperties _:x rdf:type Datatypes
properties (R1 … Rn) owl:AllDisjointProperties. _:x owl:annotatedTarget t1.
xsd:minInclusive literal in the Numbers, Restricts the value-
_:x owl:members ( R1 … Rn ).
Annotation Properties xsd:maxInclusive corresponding Time Instants space to greater than
functional FunctionalDataProperty(R) R rdf:type
xsd:minExclusive datatype (equal to) or lesser than
property owl:FunctionalProperty. named annotation A A xsd:maxExclusive (equal to) a value
property xsd:minLength Non-negative Strings, Restricts the value-
Datatype Definitions human-readable rdfs:label rdfs:label xsd:maxLength integer Binary Data, space based on the
datatype definition DatatypeDefinition(DN D) DN owl:equivalentClass D. name xsd:length IRIs lengths of the literals
human-readable rdfs:comment rdfs:comment xsd:pattern xsd:string literal Strings, Restricts the value
Assertions comment as a regular IRIs space to literals that>
additional information rdfs:seeAlso rdfs:seeAlso expression match the regular
individual equality SameIndividual(a1 … an) aj owl:sameAs aj+1. j=1…n-1
defining agent rdfs:isDefinedBy rdfs:isDefinedBy expression
individual DifferentIndividuals(a1 a2) a1 owl:differentFrom a2.
version information owl:versionInfo owl:versionInfo rdf:langRange xsd:string literal rdf:PlainLiteral Restricts the value
inequality
deprecation owl:deprecated owl:deprecated as a regular space to literals with
pairwise individual DifferentIndividuals _:x rdf:type owl:AllDifferent.
backwards owl:backwardCompatibleWith owl:backwardCompatibleWith expression language tags that
inequality (a1 … an) _:x owl:members (a1 … an).
compatibility match the regular
class assertion ClassAssertion(C a) a rdf:type C.
incompatibility owl:incompatibleWith owl:incompatibleWith expression
positive object ObjectPropertyAssertion a1 PN a2.
prior version owl:priorVersion owl:priorVersion
property assertion (PN a1 a2 )
positive data DataPropertyAssertion a R v. A HTML version of the guide is at http://www.w3.org/TR/owl2-quick-reference/
Annotation Axioms
property assertion (R a v )
negative object NegativeObjectPropertyAssertion _:x rdf:type annotation SubAnnotationPropertyOf(A1 A2) A1 rdfs:subPropertyOf A2. Copyright © 2008-2009 W3C® (MIT, ERCIM, Keio), All Rights Reserved.
property (P a1 a2 ) owl:NegativePropertyAssertion. subproperties W3C Document License: http://w3.org/brief/MTQ4
assertion _:x owl:sourceIndividual a1. annotation property AnnotationPropertyDomain(A U) A rdfs:domain U. W3C liability, trademark and document use rules apply.
_:x owl:assertionProperty P. domain
_:x owl:targetIndividual a2. annotation property AnnotationPropertyRange(A U) A rdfs:range U. Editors:
negative data NegativeDataPropertyAssertion _:x rdf:type range Jie Bao, Rensselaer Polytechnic Institute
property (R a v ) owl:NegativePropertyAssertion. Elisa F. Kendall, Sandpiper Software, Inc.
assertion _:x owl:sourceIndividual a. 2.8 Ontologies Deborah L. McGuinness, Rensselaer Polytechnic Institute
_:x owl:assertionProperty R. Peter F. Patel-Schneider, Bell Labs Research, Alcatel-Lucent
_:x owl:targetValue v. OWL ontology Ontology([ON [U]] ON rdf:type owl:Ontology. Contributors:
(importing)1 2 Import(ON1)... [ON owl:versionIRI U.] Li Ding, Rensselaer Polytechnic Institute
Keys Annotation(A t) ON owl:imports ON1. Ankesh Khandelwal, Rensselaer Polytechnic Institute
... ...
Key HasKey(C (P1 … Pm) (R1 … Rn) ) C owl:hasKey (P1 … Pm R1 … Rn). ) ON A t. ... Reference card formatting by Jie Bao
m+n>0 prefix declaration3 Prefix(p=U) @prefix p U.
Version 0.13, Oct 18 2009
2.6 Declarations 1. [ ] represents optional constructs Based on the 22 September 2009 Proposed Recommendation
2. In the RDF syntax _:x is used in place of ON if there is no ontology name ON.
class Declaration( Class( CN ) ) CN rdf:type owl:Class. 3. RDF syntax is in Turtle, other RDF serializations may vary.
datatype Declaration( Datatype( DN ) ) DN rdf:type rdfs:Datatype.
object Declaration( ObjectProperty( PN ) ) PN rdf:type
property owl:ObjectProperty.