RDF statements 'about=' <URI-reference>?

Folks,

I've just noticed that the RDF M&S document section 2.2.1, production [4], 
allows an RDF statement to have a URI-reference in an 'about=' clause.  The 
text three paragraphs below talks about a 'subcomponent' of a resource in 
relation to fragment identifiers in 'about='.

I believe this could be in conflict with the formal model, which states 
that the subject of an RDF statement is a _resource_.

 From RFC 2396:

          The resource is the conceptual mapping to an entity or set of
          entities,

a fragment identifier has meaning only in conjunction with some specific 
_entity_ associated with a resource (a MIME type is needed for it to be 
interpreted).  I'm not sure what a 'subcomponent' of a resource can be 
taken to mean.

#g
------------
Graham Klyne
(GK@ACM.ORG)