Rdf Primer / quote 23 of 55
The typed node abbreviation in RDF/XML
It is fairly common in RDF for resources to have rdf:type properties that describe the resources as instances of specific types or classes. Such resources are called typed nodes in the graph, or typed node elements in the RDF/XML. RDF/XML provides a special abbreviation for describing these typed nodes. In this abbreviation, the rdf:type property and its value are removed, and the rdf:Description element for the node is replaced by an element whose name is the QName corresponding to the value of the removed rdf:type property (a URIref that names a class).
Since a resource may be described as an instance of more than one class, a resource may have more than one rdf:type property. However, only one of these rdf:type properties can be abbreviated in this way. The others must be written out using rdf:type properties.