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Copyright©2002 W3C® (MIT, INRIA, Keio), All Rights Reserved. W3C liability, trademark, document use and software licensing rules apply.
The Resource Description Framework (RDF) is a general-purpose language for representing information in the Web. This specification describes how to use RDF to describe RDF vocabularies. This specification defines a vocabulary for this purpose and defines other built-in RDF vocabulary initially specified in the RDF Model and Syntax Specification.
This section describes the status of this document at the time of its publication. Other documents may supersede this document.
This document is a Working Draft of the World Wide Web Consortium RDF Core Working group, and has been produced as part of the Semantic Web Activity.
The Resource Description Framework is part of the W3C Semantic Web Activity. The goal of this activity, and of RDF specifically, is to produce a language for the exchange of machine-understandable information using the Web.
The RDF Vocabulary Description Language presented here is an editorial revision of the language described in the Working Draft of November 12th 2002, incorporating editorial suggestions received in review comments. Additional differences between this document and the March 27th 2000 Candidate Recommendation are described in the previous working drafts.
In conformance with W3C policy requirements, known patent and IPR constraints associated with this Working Draft are detailed on the RDF Core Working Group Patent Disclosure page.
Comments on this document are invited and should be sent to the public mailing list www-rdf-comments@w3.org. An archive of comments is available at http://lists.w3.org/Archives/Public/www-rdf-comments/.
It is inappropriate to use a W3C Working Draft as reference material or to cite them as other than "work in progress". This is work in progress and does not imply endorsement by, or the consensus of W3C. A list of current W3C Recommendations and other technical documents can be found at http://www.w3.org/TR/.
1. Introduction
2. Classes
2.1 rdfs:Resource
2.2 rdfs:Class
2.3 rdfs:Literal
2.4 rdfs:Datatype
2.5 rdf:XMLLiteral
2.6 rdf:Property
3. Properties
3.1 rdfs:range
3.2 rdfs:domain
3.3 rdf:type
3.4 rdfs:subClassOf
3.5 rdfs:subPropertyOf
3.6 rdfs:label
3.7 rdfs:comment
4. Using the Domain and Range vocabulary (Informative)
5. Other vocabulary
5.1 Container Classes and Properties
5.1.1 rdfs:Container
5.1.2 rdf:Bag
5.1.3 rdf:Seq
5.1.4 rdf:Alt
5.1.5 rdfs:ContainerMembershipProperty
5.1.6 rdfs:member
5.2 RDF Collections
5.2.1 rdf:List
5.2.2 rdf:first
5.2.3 rdf:rest
5.2.4 rdf:nil
5.3 Reification Vocabulary
5.3.1 rdf:Statement
5.3.2 rdf:subject
5.3.3 rdf:predicate
5.3.4 rdf:object
5.4 Utility Properties
5.4.1 rdfs:seeAlso
5.4.2 rdfs:isDefinedBy
5.4.3 rdf:value
6. RDF Schema summary
6.1 Classes
6.2 Properties
7. References
7.1 Normative References
7.2 Informational References
8. Acknowledgments
Appendix A RDF Schema as RDF/XML
The Resource Description Framework (RDF) defines a language for describing relationships among resources in terms of named properties and values.
This specification is one of several [RDF-PRIMER] [RDF-SYNTAX] [RDF-CONCEPTS] [RDF-SEMANTICS] [RDF-TESTS] related to RDF. The reader is referred to the RDF schema chapter in the RDF Primer [RDF-PRIMER] for an informal introduction and examples of the use of the concepts specified in this document.
This specification introduces RDF's vocabulary description language, RDF Schema. It is complemented by several companion documents which describe RDF's XML encoding [RDF-SYNTAX], mathemetical foundations [RDF-SEMANTICS] and Resource Description Framework (RDF): Concepts and Abstract Syntax [RDF-CONCEPTS]. The RDF Primer [RDF-PRIMER] provides an informal introduction and examples of the use of the concepts specified in this document.
This document is intended to provide a clear specification of the RDF vocabulary description language to those who find the formal semantics specification, RDF Semantics [RDF-SEMANTICS] daunting. Thus, this document duplicates material also specified in the RDF Semantics specification . Where there is disagreement between this document and the RDF Semantics specification, the RDF Semantics specification should be taken to be correct.
RDF properties may be thought of as attributes of resources and in this sense correspond to traditional attribute-value pairs. RDF properties also represent relationships between resources. As such, RDF data can resemble an entity-relationship diagram.
RDF however, provides no mechanisms for describing these properties, nor does it provide any mechanisms for describing the relationships between these properties and other resources. That is the role of the RDF vocabulary description language, RDF Schema. RDF Schema defines classes and properties that may be used to describe classes, properties and other resources.
This document does not specify a vocabulary of descriptive properties such as "author". Instead it specifies mechanisms that may be used to name and describe properties and the classes of resource they describe.
RDF's vocabulary description language, RDF Schema, is an extension of RDF. It provides mechanisms for describing groups of related resources and the relationships betwen these resources. RDF Schema vocabulary descriptions are written in RDF. The extra descriptive power of RDF Schema is carried in a collection of RDF resources described in this document. These resources are used to determine characteristics of other resources, such as the domains and ranges of properties.
The RDF vocabulary description language allows for a finer grained mixing of machine-processable vocabularies, and addresses the need [EXTWEB] to create metadata in which statements can draw upon multiple vocabularies that are managed in a decentralized fashion by independent communities.
The RDF vocabulary description language class and property system is
similar to the type systems of object-oriented programming languages such as
Java. However, RDF differs from many such systems in that instead of defining
a class in terms of the properties its instances may have, the RDF vocabulary
description language describes properties in terms of the classes of resource
to which they apply. This is the role of the rdfs:domain
and rdfs:range
mechanisms described in this
specification. For example, we could define the eg:author
property to have a domain of eg:Document
and a range of
eg:Person
, whereas a classical object oriented system might typically define a class eg:Book
with an attribute called eg:author
of type eg:Person
. Using the RDF approach, it is easy for others
to subsequently define additional properties with a domain of
Document
or a range of eg:Person
. This can be done
without the need to re-define the original description of these classes. One
benefit of the RDF property-centric approach is that it allows anyone to
extend the description of existing resources, one of the architectural
principles of the Web [BERNERS-LEE98].
This specification does not attempt to enumerate all the possible forms of vocabulary description that are useful for representing the meaning of RDF classes and properties. Instead, the RDF vocabulary description strategy is to acknowledge that there are many techniques through which the meaning of classes and properties can be described. Richer vocabulary or 'ontology' languages such as DAML+OIL, the W3C Owl languages, inference rule languages and other formalisms (for example temporal logics) will each contribute to our ability to capture meaningful generalizations about data in the Web. RDF vocabulary designers can create and deploy Semantic Web applications using the RDF vocabulary description language 1.0 facilities, while exploring richer vocabulary description languages that share this general approach.
The language defined in this specification consists of a collection of RDF resources that can be used to describe properties of other RDF resources (including properties) in application-specific RDF vocabularies. The core vocabulary is defined in a namespace informally called 'rdfs' here. That namespace is identified by the URI-Reference http://www.w3.org/2000/01/rdf-schema# and is associated with the prefix 'rdfs'. This specification also uses the prefix 'rdf' to refer to the core RDF namespace http://www.w3.org/1999/02/22-rdf-syntax-ns#.
For convenience and readability, this specification uses an abbreviated form to represent URI-References. A name of the form prefix:suffix should be interpreted as a URI-Reference consisting of the URI-Reference associated with the prefix concatenated with the suffix.
Editorial Note: this Working Draft does not propose a change to the namespace URIs used, nor to the prefix 'rdfs' traditionally used to indicate the vocabulary description language's namespace URI . The Working Group seek feedback from implementors on the costs and benefits of moving to a new RDFS namespace URI.
Resources may be divided into groups called classes. The members of a
class are known as instances of the class. Classes are themselves
resources. They are often identified by RDF
URI References and may be described using RDF properties. The rdf:type
property may be used to state that a
resource is an instance of a class.
RDF distinguishes between a class and the set of its instances. Associated with each class is a set, called the class extension of the class, which is the set of the instances of the class. Two classes may have the same set of instances but be different classes. For example, the tax office may define the class of people living at the same address as the editor of this document. The Post Office may define the class of people whose address has the same zip code as the address of the author. It is possible for these classes to have exactly the same instances, yet to have different properties. Only one of the classes has the property that it was defined by the tax office, and only the other has the property that it was defined by the Post Office.
A class may be a member of its own class extension and thus may be an instance of itself. Note that if a class were the same thing as the set of its instances then common (Zermelo-Fraenkel) set theory would prevent it being an instance of itself.
The group of resources that are RDF vocabulary description language
classes is itself a class called rdfs:Class
.
A class C is a subclass of a class C' if and only if all the instances of C are also instances of C'. All classes are subclasses of themselves. The rdfs:subClassOf property may be used to state that one class is a subclass of another. The term super-class is used as the inverse of subclass. A class C' is a super-class of a class C if and only if C is a subclass of C'.
The RDF Concepts and Abstract Syntax [RDF-CONCEPTS] specification defines the RDF concept of an RDF datatype. All datatypes are classes. The instances of a class that is a datatype are the members of the value space of the datatype.
All things described by RDF are called resources, and are
instances of the class rdfs:Resource
. This is the class of
everything. All other classes are subclasses of
this class. rdfs:Resource
is an instance of rdfs:Class
.
This is the class of resources that are RDF classes.
rdfs:Class
is an instance of rdfs:Class.
The class rdfs:Literal
is the class of literal values such as
strings and integers. Property values such as textual strings are examples of
RDF literals. Literals may be plain or typed. A typed literal is an instance
of a datatype class. This specification does not define the class of plain
literals.
rdfs:Literal
is an instance of rdfs:Class
. rdfs:Literal is a subclass of rdfs:Resource.
rdfs:Datatype
is the class of datatypes. All instances of
rdfs:Datatype
correspond to the RDF
model of a datatype described in the RDF Concepts specification [RDF-CONCEPTS]. rdfs:Datatype
is
both an instance of and a subclass of rdfs:Class
. Each instance of rdfs:Datatype
is a subclass of rdfs:Literal.
The class rdf:XMLLiteral
is the class of XML
literal values. rdf:XMLLiteral
is an instance of
rdfs:Datatype
and a subclass of rdfs:Literal
.
rdf:Property
is the class of RDF properties.
rdf:Property
is an instance of rdfs:Class
.
The RDF Concepts and Abstract Syntax specification [RDF-CONCEPTS] defines the concept of an RDF property as a relation between subject resources and object resources.
This specification defines the concept of subproperty. A property P is a subproperty of property P' if and only if all subjects and objects related by P are also related by P'. All properties are subproperties of themselves. The term super-property is often used as the inverse of subproperty, i.e. P is a super-property of P' if and only if P' is a subproperty of P. This specification does not define a top property that is the super-property of all properties.
rdfs:range
is an instance of rdf:Property
that is used to state that
the values of a property are instances of one or more classes.
The triple
P rdfs:range C
states that P is an instance of the class rdf:Property
, that C is an instance of the class rdfs:Class and that the objects of triples whose predicate is P are instances of the class C.
Where P has more than one rdfs:range property, then the objects of triples
with predicate P are instances of all the classes stated by the
rdfs:range
properties.
The rdfs:range
property can be applied to itself. The rdfs:range of rdfs:range
is the class rdfs:Class
. This states that any resource
that is the value of an rdfs:range
property is an instance of rdfs:Class
.
The rdfs:range
property is only applied to properties. This
can also be represented in RDF using the rdfs:domain
property. The rdfs:domain
of rdfs:range
is the class rdf:Property
. This states
that any resource with an rdfs:range
property is an instance of
rdf:Property
.
rdfs:domain
is an instance of rdf:Property
that is used to state that
any resource that has a given property is an instance of one or more
classes.
A triple of the form:
P rdfs:domain C
states that P is an instance of the class rdf:Property, that C is a instance of the class rdfs:Class and that the subjects of triples whose predicate is P are instances of the class C.
Where a property P has more than one rdfs:domain property, then the
subjects of triples with predicate P are instances of all the classes stated
by the rdfs:domain
properties.
The rdfs:domain
property may be applied to itself. The rdfs:domain of rdfs:domain
is the class rdf:Property
. This states that any
resource with an rdfs:domain
property is an instance of rdf:Property
.
The rdfs:range
of
rdfs:domain
is the class rdfs:Class. This states that any resource that is the value of an rdfs:domain
property is an instance of
rdfs:Class
.
rdf:type
is an instance of rdf:Property
that is used to state that
a resource is an instance of a class.
A triple of the form:
R rdf:type C
states that C is an instance of rdfs:Class
and R is an instance of C.
The rdfs:domain
of rdf:type
is rdfs:Resource. The rdfs:range
of rdf:type is rdfs:Class
.
The property rdfs:subClassOf
is an instance of rdf:Property that is used to state that one class is a specialization of another.
A triple of the form:
C1 rdfs:subClassOf C2
states that C1 is an instance of rdfs:Class
, C2 is an instance of rdfs:Class
and C1 is a subclass of C2. The rdfs:subClassOf
property is transitive.
The rdfs:domain
of
rdfs:subClassOf
is rdfs:Class. The rdfs:range
of rdfs:subClassOf
is rdfs:Class
.
The property rdfs:subPropertyOf
is an instance of rdf:Property that is used to specify that one property is a specialization of another.
A triple of the form:
P1 rdfs:subPropertyOf P2
states that P1 is an instance of rdf:Property
, P2 is an instance of rdf:Property
and P1 is a subproperty of P2. The
rdfs:subPropertyOf
property is transitive.
The rdfs:domain
of
rdfs:subPropertyOf
is rdf:Property
. The rdfs:range
of rdfs:subPropertyOf is rdf:Property
.
The rdfs:label
property is used to provide a human-readable
version of a resource's name.
A triple of the form:
R rdfs:label L
states that L is a human readable label for R.
The rdfs:domain
of
rdfs:label
is rdfs:Resource
. The rdfs:range
of rdfs:label is rdfs:Literal
.
Multilingual labels are supported using the language tagging facilityof RDF literals.
The rdfs:comment
property is used to provide a human-readable
description of a resource.
A triple of the form:
R rdfs:comment L
states that L is a human readable description of R.
The rdfs:domain
of
rdfs:label
is rdfs:Resource
. The rdfs:range
of rdfs:comment is rdfs:Literal
.
A textual comment helps clarify the meaning of RDF classes and properties. Such in-line documentation complements the use of both formal techniques (Ontology and rule languages) and informal (prose documentation, examples, test cases). A variety of documentation forms can be combined to indicate the intended meaning of the classes and properties described in an RDF vocabulary. Since RDF vocabularies are expressed as RDF graphs, vocabularies defined in other namespaces may be used to provide richer documentation.
Multilingual documentation is supported through use of the language tagging facility of RDF literals.
This specification introduces an RDF vocabulary for describing the meaningful use of properties and classes in RDF data. For example, an RDF vocabulary might describe limitations on the types of values that are appropriate for some property, or on the classes to which it makes sense to ascribe such properties.
RDF Schema provides a mechanism for describing this information, but does
not say whether or how an application should use it. For example, while an
RDF vocabulary can assert that an author
property is used to
indicate resources that are instances of the class Person
, it does not say whether or how an application should act in processing that range information. Different applications will use this information in different ways. For example, data checking tools might use this to help discover errors in some data set, an interactive editor might suggest appropriate values, and a reasoning application might use it to infer additional information from instance data.
RDF vocabularies can describe relationships between vocabulary items from multiple independently developed vocabularies. Since URI-References are used to identify classes and properties in the Web, it is possible to create new properties that have a domain
or range
whose value
is a class defined in another namespace.
Additional classes and properties, including constructs for representing containers and RDF statements, and for deploying RDF vocabulary descriptions in the World Wide Web are defined in this section.
RDF containers are resources that are used to represent collections. An introduction to RDF containers with examples may be found in the RDF Primer [RDF-PRIMER]. The same resource may appear in a container more than once. Unlike containment in the physical world, a container may be contained in itself.
Three different kinds of container are defined. Whilst the formal semantics [RDF-SEMANTICS] of all three classes of container are identical different classes may be used to indicate informally further information. An rdf:Bag is used to indicate that the container is intended to be unordered. An rdf:Seq is used to indicate that the order indicated by the numerical order of the container member ship properties of the container is intended to be significant. An rdf:Alt container is used to indicate that typical processing of the container will be to select one of the members.
Just as a hen house may have the property that it is made of wood, that does not mean that all the hens it contains are made of wood, a property of a container is not necessarily a property of all of its members.
RDF containers are defined by the following classes and properties.
The rdfs:Container
class is a super-class of the RDF Container classes, i.e. rdf:Bag
, rdf:Seq
, rdf:Alt
.
The rdf:Bag
class is the class of RDF 'Bag' containers. It is
a subclass of rdfs:Container
. Whilst formally it is no
different from an rdf:Seq
or an rdf:Alt
, the rdf:Bag
class is used conventionally to indicate to a human reader that the container is intended to be unordered.
The rdf:Seq
class is the class of RDF 'Sequence' containers.
It is a subclass of rdfs:Container
. Whilst formally it is no
different from an rdf:Bag
or an rdf:Alt
, the rdf:Seq
class is used
conventionally to indicate to a human reader that the numerical ordering of
the container membership
properties of the container is intended to be significant.
The rdf:Alt
class is the class of RDF 'Alternative'
containers. It is a subclass of rdfs:Container
. Whilst formally it is no
different from an rdf:Seq
or an rdf:Bag
, the rdf:Alt
class is used
conventionally to indicate to a human reader that typical processing will be
to select one of the members of the container. The first member of the
container, i.e. the value of the rdf:_1
property, is the
default choice.
The rdfs:ContainerMembershipProperty
class has as instances
the properties rdf:_1, rdf:_2, rdf:_3 ...
that are used to state
that a resource is a member of a container.
rdfs:ContainerMembershipProperty
is a subclass of rdf:Property
. Each instance of rdfs:ContainerMembershipProperty
is an rdfs:subPropertyOf
the rdfs:member
property.
Given a container C, a triple of the form:
C rdf:_nnn O
where nnn is the decimal representation of an integer greater than 0 with no leading zeros, states that O is a member of the container C.
Container membership properties may be applied to resources other than containers.
rdfs:member
is an instance of rdf:Property
that is a super-property of all the container membership properties i.e. each container membership property has an rdfs:subPropertyOf
relationship
to the property rdfs:member
.
The rdfs:domain
of
rdfs:member
is rdfs:Resource
. The rdfs:range
of rdfs:member
is
rdfs:Resource
.
RDF containers are open in the sense that the core RDF specifications define no mechanism to state that there are no more members. The RDF Collection vocabulary of classes and properties can describe a closed collection, i.e. one that can have no more members. The reader is referred to the collections section of the RDF primer for an informal introduction to collections with examples.
A collection is represented as a list of items, a representation that will be familiar to those with experience of Lisp and similar programming languages. There is a shorthand notation in the RDF/XML syntax specification [RDF-SYNTAX] for representing collections.
rdf:List
is the class of RDF Lists.
rdf:first
is an instance of rdf:Property
that is used to indicate
the first item of a list.
A triple of the form:
L rdf:first O
states that L is an instance of rdf:List
and that O is the first item of the
list.
The rdfs:domain
of
rdf:first
is rdf:List.
The rdfs:range
of
rdf:first
is rdfs:Resource
.
rdf:rest
is an instance of rdf:Property
that is used to indicate the sublist that contains the items of a list other than the first.
A triple of the form:
L rdf:rest O
states that L is an instance of rdf:List
, that O is an instance of rdf:List
and O is the list L without L's first
item.
The rdfs:domain
of
rdf:rest
is rdf:List
. The rdfs:range
of rdf:rest
is
rdf:List
.
The resource rdf:nil
is an instance of rdf:List
that is the empty list.
A triple of the form:
L rdf:rest rdf:nil
states that L is an instance of rdf:List
that has one element which should be
indicated by its rdf:first
property.
The original RDF Model and Syntax Specification [RDFMS] defined vocabulary for describing RDF statements without stating them. This section describes that vocabulary. An informal introduction to the reification vocabulary, with examples, may be found in the RDF Primer [RDF-PRIMER].
rdf:Statement
is an instance of rdfs:Class.
It is the class of RDF statements. An RDF statement is the statement made by an RDF triple. The subject of an RDF statement is the instance of rdfs:Resource
identified by the subject of the triple. The predicate of an RDF statement is the instance of rdf:Property
identified by the predicate of the triple. The object of an RDF statement is the instance of rdfs:Resource
identified by the object of the triple.
rdf:Statement
is the
domain of the properties rdf:predicate
, rdf:subject
and rdf:object
. Different individual rdf:Statement
instances may have the
same values for their rdf:predicate
,
rdf:subject
and rdf:object
properties.
rdf:subject
is an instance of rdf:Property
that is used to state the
subject of a statement.
A triple of the form:
S rdf:subject R
states that S is an instance of rdf:Statement
and that the subject of S is R.
The rdfs:domain
of rdf:subject
is
rdf:Statement
. The rdfs:range
of
rdf:subject
is rdfs:Resource
.
rdf:predicate is an instance of rdf:Property
that is used to state the
predicate of a statement.
A triple of the form:
S rdf:predicate P
states that S is an instance of rdf:Statement
, that P is an instance of rdf:Property
and that the predicate of S is P.
The rdfs:domain
of
rdf:predicate
is rdf:Statement
and the rdfs:range
is rdf:Property
.
rdf:object is an instance of rdf:Property
that is used to state the
object of a statement.
A triple of the form:
S rdf:object O
states that S is an instance of rdf:Statement
and that the object of S is O.
The rdfs:domain
of
rdf:object
is rdf:Statement
. The rdfs:range
of
rdf:object
is rdfs:Resource
.
The following utility classes and properties are defined in the RDF core namespaces.
rdfs:seeAlso
is an instance of rdf:Property
that is used to indicate a
resource that might provide additional information about the subject
resource.
A triple of the form:
S rdfs:seeAlso O
states that the resource O may provide additional information about S. It may be possible to retrieve representations of O from the Web, but this is not required. When such representations may be retrieved, no constraints are placed on the format of those representations.
The rdfs:domain
of rdfs:seeAlso
is rdfs:Resource
. The rdfs:range
of rdfs:seeAlso
is rdfs:Resource
.
rdfs:isDefinedBy
is an instance of rdf:Property
that is used to indicate a
resource defining the subject resource. This property may be used to indicate
an RDF vocabulary in which a resource is described.
A triple of the form:
S rdfs:isDefinedBy O
states that the resource O defines S. It may be possible to retrieve
representations of O from the Web, but this is not required. When such
representations may be retrieved, no constraints are placed on the format of
those representations. rdfs:isDefinedBy
is a subproperty of rdfs:seeAlso
.
The rdfs:domain
of rdfs:isDefinedBy
is rdfs:Resource
. The rdfs:range
of rdfs:isDefinedBy
is rdfs:Resource
.
rdf:value
is an instance of rdf:Property
that may be used in
describing structured values.
rdf:value has no meaning on its own. It is provided as a piece of vocabulary that may be used in idioms such as illustrated in example 16 of the RDF primer [RDF-PRIMER]. Despite the lack of formal specification of the meaning of this property, there is value in defining it to encourage the use of a common idiom in examples of this kind.
The rdfs:domain
of rdf:value
is rdfs:Resource
. The rdfs:range
of rdf:value
is rdfs:Resource
.
This table presents an overview of the vocabulary of RDF, drawing together vocabulary originally defined in the RDF Model and Syntax specification with classes and properties that originate with RDF Schema.
Class name | comment |
---|---|
rdfs:Resource | The class resource, everything. |
rdfs:Literal | The class of literal values, e.g. textual strings and integers. |
rdf:XMLLiteral | The class of XML literals. |
rdfs:Class | The class of classes. |
rdf:Property | The class of RDF properties. |
rdfs:Datatype | The class of RDF datatypes. |
rdf:Statement | The class of RDF statements. |
rdf:Bag | The class of unordered containers. |
rdf:Seq | The class of ordered containers. |
rdf:Alt | The class of containers of alternatives. |
rdfs:Container | The class of RDF containers. |
rdfs:ContainerMembershipProperty | The class of container membership properties, rdf:_1, rdf:_2, ..., all of which are sub-properties of 'member'. |
rdf:List | The class of RDF Lists. |
Property name | comment | domain | range |
---|---|---|---|
rdf:type | the subject is an instance of a class. | rdfs:Resource | rdfs:Class |
rdfs:subClassOf | the subject is a subclass of a class. | rdfs:Class | rdfs:Class |
rdfs:subPropertyOf | the subject is a subproperty of a property. | rdf:Property | rdf:Property |
rdfs:domain | a domain of the subject property. | rdf:Property | rdfs:Class |
rdfs:range | a range of the subject property. | rdf:Property | rdfs:Class |
rdfs:label | a human-readable name for the subject. | rdfs:Resource | rdfs:Literal |
rdfs:comment | a description of the subject resource. | rdfs:Resource | rdfs:Literal |
rdfs:member | a member of the subject container. | rdfs:Resource | rdfs:Resource |
rdf:first | the first item in the subject RDF list. | rdf:List | rdfs:Resource |
rdf:rest | the rest of the subject RDF list after the first item. | rdf:List | rdf:List |
rdfs:seeAlso | further information about the subject resource. | rdfs:Resource | rdfs:Resource |
rdfs:isDefinedBy | the definition of the subject resource. | rdfs:Resource | rdfs:Resource |
rdf:value | idiomatic property used for structured values (see the RDF Primer for an example of its usage). | rdfs:Resource | rdfs:Resource |
rdf:subject | the subject of the subject RDF statement. | rdf:Statement | rdfs:Resource |
rdf:predicate | the predicate of the subject RDF statement. | rdf:Statement | rdf:Property |
rdf:object | the object of the subject RDF statement. | rdf:Statement | rdfs:Resource |
In addition to these classes and properties, RDF also uses properties
called rdf:_1
, rdf:_2
, rdf:_3
... etc.,
each of which is both a sub-property of rdfs:member
and an
instance of the class rdfs:ContainerMembershipProperty
. There is
also an instance of rdf:List
called rdf:nil
that is
an empty rdf:List
.
The RDF Schema design was originally produced by the RDF Schema Working Group (1997-2000). The current specification is largely an editorial clarification of that design, and has benefited greatly from the hard work of the RDF Core Working Group members, and from implementation feedback from many members of the RDF Interest Group.
David Singer of IBM was the chair of the original RDF Schema group throughout most of the development of this specification; we thank David for his efforts and thank IBM for supporting him and us in this endeavor. Particular thanks are also due to Andrew Layman for his editorial work on early versions of this specification.
The original RDF Schema Working Group membership included:
Nick Arnett (Verity), Dan Brickley (ILRT / University of Bristol), Walter Chang (Adobe), Sailesh Chutani (Oracle), Ron Daniel (DATAFUSION), Charles Frankston (Microsoft), Joe Lapp (webMethods Inc.), Patrick Gannon (CommerceNet), RV Guha (Epinions, previously of Netscape Communications), Tom Hill (Apple Computer), Renato Iannella (DSTC), Sandeep Jain (Oracle), Kevin Jones, (InterMind), Emiko Kezuka (Digital Vision Laboratories), Ora Lassila (Nokia Research Center), Andrew Layman (Microsoft), John McCarthy (Lawrence Berkeley National Laboratory), Michael Mealling (Network Solutions), Norbert Mikula (DataChannel), Eric Miller (OCLC), Frank Olken (Lawrence Berkeley National Laboratory), Sri Raghavan (Digital/Compaq), Lisa Rein (webMethods Inc.), Tsuyoshi Sakata (Digital Vision Laboratories), Leon Shklar (Pencom Web Works), David Singer (IBM), Wei (William) Song (SISU), Neel Sundaresan (IBM), Ralph Swick (W3C), Naohiko Uramoto (IBM), Charles Wicksteed (Reuters Ltd.), Misha Wolf (Reuters Ltd.)
An RDF description of the RDF Core vocabulary is given here in RDF/XML serialization syntax. Please note that the namespace URI for the RDF Schema vocabulary could change in future versions of this specification. This RDF schema includes statements describing RDF resources originally introduced by the 1999 RDF Model and Syntax specification, as well as definitions for resources introduced in the RDF Core Schema vocabulary.
This RDF/XML is also available as a separate RDF/XML document (rdfs-namespace.xml). It is not currently published at the W3C RDF Schema namespace URI.@@@
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