This is the class of resources that are RDF classes. rdfs:Class is an instance of rdfs:Class, and is the class of classes.


    <rdfs:Class rdf:about="http://www.w3.org/2000/01/rdf-schema#Class">

        <rdfs:isDefinedBy rdf:resource="http://www.w3.org/2000/01/rdf-schema#"/>


        <rdfs:comment>The class of classes.</rdfs:comment>

        <rdfs:subClassOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>


Example listing




    <rdf:Description rdf:ID="MotorVehicle">

        <rdf:type rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class"/>


or, abbreviated:

    <rdfs:Class rdf:ID="MotorVehicle"/>

Other information

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 may be an instance of itself.

The group of resources that are RDF Schema classes is itself a class called rdfs:Class.

If a class C is a subclass of a class C', then all instances of C will also be instances of C'. 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. If a class C' is a super-class of a class C, then all instances of C are also instances 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.

Use in ISO 15926