Re: Is a namespace a resource? - was: duck

Al Gilman scripsit:

> Can we, really?  That is compatible with the status quo.  If one wishes, in
> RDF, to decorate a namespace with assertions, can we identify the namespace
> similarly?  E.g.
> 
> "The namespace which uses <ns-attr value> in its namespace declaration in
> XML instances has characteristic <assertion>."

Yes.  RDF provides support for making statements about resources which are
embedded directly in the RDF.  Most often, such resources are proxies for
things (people, bricks, etc.) that do not (yet) have URIs.  

Suppose that the namespace "foo.html" is declared in a document
whose URI is "http://www.foo.com/docs/TheDoc.xml".
And suppose the RDF document "http://www.example.com/rdf/MyRDF.rdf"
contains the following element:

	<rdf:Description id="humma">
		<ns:name>foo.html</ns:name>
		<ns:element-count>34</ns:element-count>
	<rdf:Description>

This creates a resource whose URI is
"http:/www.example.com/rdf/MyRDF.rdf#humma", which
is said to have two string properties, a name and an element-count.
RDF natively understands only two types of properties, string and URI.

Of course it would be an error to make the ns:name property of type URI,
because then we would assert that the namespace name is
"http://www.example.com/rdf/foo.html", which is by no means the case.

Note the namespace prefix "ns"; this would be bound to a namespace of
properties suitable for describing namespaces.

> There has been repeated assertion to the effect that RDF can't do this;
> that it requires a URI to refer to.   If this is not actually true, if we
> can use this sort of query to isolate the namespace instead of requiring
> the unsupported infrastructure of a definition and a name, we would be
> ahead on continuity+capability.

RDF does require a URI, but the URI can refer to a resource within the
RDF document itself, as we see here.

-- 
John Cowan                                   cowan@ccil.org
	"You need a change: try Canada"  "You need a change: try China"
		--fortune cookies opened by a couple that I know

Received on Tuesday, 6 June 2000 11:38:26 UTC