rdf:Description and rdf:about not defined in RDF namespace document

Hi all

Aside the debate of RDF namespace, I was looking at
http://www.w3.org/1999/02/22-rdf-syntax-ns document which is supposed to
define all elements in RDF namespace. But it does not define some of the
most used elements in this namespace : rdf:Description and rdf:about.
I was not aware of this, and it triggers two questions :
Why are not they defined is this document?
Where else are they defined?

The point is that if I dereference
http://www.w3.org/1999/02/22-rdf-syntax-ns#about it leads me to a document
where this URI is used but not defined.

Providing it's defined somewhere, would it be correct to say that rdf:about
is a datatype property with range xsd:anyURI?
Does the following triple holds?
<http://example.org/foo>  rdf:about  "http://example.org/foo"^^xsd:anyURI

Thanks for any clarification

-- 

*Bernard Vatant *
Vocabularies & Data Engineering
Tel :  + 33 (0)9 71 48 84 59
Skype : bernard.vatant
http://google.com/+BernardVatant
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