RDF Schema

1. Using RDF to define RDF Schema
 - RDF Schema (RDFS) is an RDF vocabulary which contains ...
  1) Classes for defining classes and properties
   * class definitions
   <rdf:Description rdf:about="#Person">
      <rdf:type rdf:resource="&rdfs;Class"/>
   </rdf:Description>
               ↓
    <rdfs:Class rdf:about="#Person"/>

   * Employee is a subclass of Person
   <rdfs:Class rdf:about="#Employee">
      <rdfs:subClassOf rdf:resource="#Person"/>
   </rdfs:Class>

   * rdfs:subClassOf is transitive: (A rdfs:subClassOf B) and (B rdfs:subClassOf C) implies (A rdfs:subClassOf C)
   * rdfs:subClassOf is reflexive: All classes are subclasses of themselves
   * rdf:type distributes over rdf:subClassOf: (A rdfs:subClassOf B) and (C rdf:type A) implies (C rdf:type B)

  2) Properties for defining basic characteristics of classes and properties
   * property definitions
   <rdf:Description rdf:about="#worksFor">
      <rdf:type rdf:resource="&rdfs;Property"/>
   </rdf:Description>
               ↓
    <rdf:Property rdf:about="#worksFor"/>

   * The property worksFor relates objects of class Employee to objects of class Company
   <rdf:Property rdf:about="#worksFor">
      <rdfs:domain rdf:resource="#Employee"/> /* the class that the property runs from */
      <rdfs:range rdf:resource="#Company"/>           /* the class that the property runs to */
   </rdf:Property>

   * worksFor is a subproperty of affiliatedTo
   <rdf:Propertyrdf:about="#worksFor ">
      <rdfs:subPropertyOf rdf:resource="#affiliatedTo"/>
   </rdf:Property>

   * rdfs:subClassOf is transitive and reflexive

  3) Some ancillary properties
   * rdfs:label is used to give a human readable name for a resource
   * rdfs:comment is used to give a human readable description for a resource
   * rdfs:seeAlso is used to indicate a resource which can be retrieved to give more information about something

https://en.wikipedia.org/wiki/RDF_Schema

https://www.w3.org/TR/rdf-schema/