RE: [xdi] Groups - XDI RDF v8 Comments-Barnhill (pdf) (XDI RDF v8 Commen

Just to be clear, the “n-segment” syntax was deprecated in the V9 XDI RDF Model document (http://wiki.oasis-open.org/xdi/XdiRdfModel) due to the problems identified in this thread. To be precise, it was unclear whether

meant that s1/p1/o1 was the subject of p2/o2 or not. It was also unclear how cross-reference syntax would be applied.

We solved both problems by eliminating “n-segment” syntax in the V9 document. Now it should be unambiguous that if you want to express that s1/p1/o1 is the subject of p2/o2, you say:

(s1/p1/o1)/p2/o2

What did remain is the // syntax for subcontexts, which allows you to solve the RDF “blank node problem” by providing an address for a blank node. That address is simply // (which fits very nicely from a conceptual standpoint since the identifier for that segment is “blank”).

So if I want to say that the object of s1/p1 is a blank node, I can write it as s1/p1// . This creates a new XDI context in which I can express another set of XDI statements whose XRIs are unique in this context.

We’ll go over the practical uses for this on the call tomorrow – agenda coming out shortly.

=Drummond

From: markus.sabadello@gmail.com [mailto:markus.sabadello@gmail.com] On Behalf Of Markus Sabadello
Sent: Wednesday, March 12, 2008 10:44 AM
To: Giovanni Bartolomeo
Cc: barnhill_william@bah.com; xdi@lists.oasis-open.org
Subject: Re: [xdi] Groups - XDI RDF v8 Comments-Barnhill (pdf) (XDI RDF v8 Comments-Barnhill.pdf) uploaded

To be honest, I don't really understand the N-Segment syntax anyway.

Why is

s1
        p1
                 o1
                          p2
                                   o2

better than

s1
        p1
                 o1
o1
        p2
                 o2

?

Markus

On Tue, Mar 11, 2008 at 4:29 PM, Giovanni Bartolomeo <giovanni.bartolomeo@uniroma2.it> wrote:

Dear Bill, All,

reading your comments about XDI RDF v8 ( http://www.oasis-open.org/committees/download.php/27112/XDI%20RDF%20v8%20Comments-Barnhill.pdf ) I've found this sentence:

One problem with the 3-Segment syntax is that the N-Segment syntax uses cross-references for
reification. This means 3-Segment syntax has to have a different notation for a subject which is the
statement itself rather than the object of the statement. The 3-Segment notation for this is a crossreference
within a cross-reference: (()). So a subject of (s/p/o) asserts s/p/o and starts a new statement
whose subject is o, while a subject of ((s/p/o)) asserts s/p/o and starts a new statement whose subject is
the statement s/p/o. For example to say that =Drummond is author of the statement =Bill.Barnhill is a
contributor to the resource represented by @example we would use the XRI:
((@example/+dc+contributor/=Bill.Barnhill))/+dc+author/=Drummond.

Well, I'm wondering how N3 syntax (and consequently X3 simple) addresses this problem:

If my understanding is correct, the N3 syntaxt
<s1> <p1> <o1>
<o1> <p2> <o2>
is equivalent to X3 simple
s1
        p1
                 o1
                          p2
                                   o2
what if I want to express that the whole statement <s1> <p1> <o1> is the subject of <p2> <o2>? How this can be represented with X3 Simple?
Breaking into a new subcontext doesn't seem to help, as this explicitly introduce a new subject!
s1
        p1
                 /
                          s2
                                   p2
                                            o2
Whereas I just want that the whole statement (s1/p1/o1) is the subject of p2!

What do you think? Am I missing something?

Thanks,
Giovanni

At 11.06 07/02/2008, barnhill_william@bah.com wrote:

The document named XDI RDF v8 Comments-Barnhill (pdf) (XDI RDF v8 Comments-Barnhill.pdf) has been submitted by Mr. William Barnhill to the OASIS XRI Data Interchange (XDI) TC document repository. Document Description: View Document Details: http://www.oasis-open.org/apps/org/workgroup/xdi/document.php?document_id=27112 Download Document: http://www.oasis-open.org/apps/org/workgroup/xdi/download.php/27112/XDI%20RDF%20v8%20Comments-Barnhill.pdf PLEASE NOTE: If the above links do not work for you, your email application may be breaking the link into two pieces. You may be able to copy and paste the entire link address into the address field of your web browser. -OASIS Open Administration No virus found in this incoming message.
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