RE: Extracting and reifying RDF statements from XML

Jos,

>
>
> On 22 september 2000 Jonathan Borden wrote:
> > This extractor outputs rdf:Statements.
>
> Nice! Our samples passed.
>
> > Interestingly, when the result of a transform is itself
> > transformed, the statements are reified, hence I call
> > this rdfExtractify.xsl
>
> I think rdf:Statement is axiomatic and should not be
> further reified. So reified RDF is invariant after such
> transformation (i.e. producing the same graph).

I must admit that I am only vaguely aware of the purpose of reification but
reading M&S 1.0 http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/#model

"Furthermore, the formal specification for reification is:

7. There is an element of Resources, not contained in Properties, known as
RDF:Statement.
8. There are three elements in Properties known as RDF:predicate,
RDF:subject and RDF:object.
9. Reification of a triple {pred, sub, obj} of Statements is an element r of
Resources representing the reified triple and the elements s1, s2, s3, and
s4 of Statements such that
s1: {RDF:predicate, r, pred}
s2: {RDF:subject, r, subj}
s3: {RDF:object, r, obj}
s4: {RDF:type, r, [RDF:Statement]}
"

It seems to me that under [9], an <rdf:Statement> which is a triple, is what
is being reified. I am confused as to why you suggest that rdf:Statement
should not be further reified.

Jonathan Borden
The Open Healthcare Group
http://www.openhealth.org