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   Re: RDF? TM? (was Re: Didier's lab report)

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  • From: Nikita Ogievetsky <nogievet@cogx.com>
  • To: Uche Ogbuji <uche.ogbuji@fourthought.com>
  • Date: Thu, 14 Dec 2000 12:15:48 -0500

Hello Uche,

You wrote:
> Sure.  And here's just one of ten vigintillion ways to express this in RDF
> right in the original XML

Well I do not know about vigintillion but definitely there are zillion ways
of expressing it in XTM :-))
(I am not sure though that this should be counted as an advantage?)

> <MyOriginElement rdf:ID="origin1">
>   <incstyle:remotestyle>
>     <rdf:Alt>
>       <incstyle:sheet incstyle:case="WML" xlink:href="wml.xslt"/>
>       <incstyle:sheet incstyle:case="IE5" xlink:href="ie.xslt"
> incstyle:param="version=5"/>
>       <incstyle:sheet incstyle:case="IE4" xlink:href="ie.xslt"
> incstyle:param="version=4"/>
>       <incstyle:sheet incstyle:case="other" xlink:href="default.xslt"/>
>     </rdf:Alt>
>   </incstyle:remotestyle>
> </MyOriginElement>
> Again, I even included a few bonuses, and it's still quite simple.  Of
> course it does illustrate another of RDF's annoyances: that you must
> have a namespace on all attributes if you wish to them to be considered
> abbreviated properties.

OK, syntax looks nice. How about the meaning of it?
I would wonder to see the RDF schema behind "incstyle" namespace.
Please agree that no graph can be built for your example without knowing the

How do you know that WML is "Wireless Markup Language"
and not  "Woman Man Love"?
And how do you know that sheet is an XSLT stylesheet and not ... sheetrock?
> And RDF is flexible enough that you can also express this without a single
> "rdf" element or attribute besides the envelopes.
> > (XTM topic can also have a real-world subject, one that can not be
> > directly.
> So can RDF with anonymous resources.
> > In this case "the subject may be indicated through one or more resources
> > that describe the subject" -- xtm spec.)
> >
> > In any case, could you give an equivalent to the above example that uses
> > triples? Would you like to go for this exercise?
> Your statement makes me wonder how you understand the role of "triples" in
> RDF.  I get  the impression that you might not realize that they are
> simply a database and list-processing convenient representation of the
> RDF abstract model, which is a graph, just like TM's.

Yes, but because XTM allows n-ary associations there are less nodes in the

Well ... I must confess that I was also getting "the impression that you
might not realize that "
nothing is hardcoded in Topic Maps :-))

By the way, if it sounds that I dislike RDF for some reason, it is wrong.
I believe that there are certain things that are better in RDF and certain
things that are better in Topic Maps. I hope that this discussion can make
this distinction a little clearer.

> You can work with RDF just fine without worrying about constructing
> "triples" if you like.  You can use the graph or the XML serialization.

Although XTM syntax in my example looks a little more verbose then RDF in
your example,
it stands much closer to the XTM processing model (then your example to the
RDF graph).
The final graph and the meaning are things that really counts.

The following fragment looks even more concise then the example you
   <sheet case="WML" href="wml.xslt"/>
   <sheet case="IE5" href="ie.xslt" param="5"/>
   <sheet scope="IE4" href="wml.xslt" param="4"/>
   <sheet scope="other" href="default.xslt" param="4"/>
You know that it is very easy to write a stylesheet to go from this fragment
your RDF or my XTM examples.
So conciseness is not the main issue.
Although some times it is desirable, for example when expressing properties.
And this is were RDF is a little ahead. :-))
Yes, I do believe that we should try to use the best of both worlds...



Nikita Ogievetsky, Cogitech Inc.
Consultant in XML/XSLT/Xlink/TopicMaps
Cogito Ergo XML


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