W3C home > Mailing lists > Public > www-rdf-interest@w3.org > August 2001

Re: Using urn:publicid: for namespaces

From: Sean B. Palmer <sean@mysterylights.com>
Date: Tue, 14 Aug 2001 00:00:26 +0100
Message-ID: <03df01c12452$d1ca5160$43dd93c3@z5n9x1>
To: <Patrick.Stickler@nokia.com>, <scranefield@infoscience.otago.ac.nz>, <www-rdf-interest@w3.org>
> > I did send a letter about this to www-rdf-interest a
> > short while ago; perhaps you missed it :-)
>
> I must have. Can you send me a copy?

I can do better than that: I can give you a URL! [1] from RDF
Interest, last month.

[...]
> > [ :ns <http://www.w3.org/1999/xhtml>; :expEType "title" ] .
[...]
> Firstly, I don't see how the above is a valid URI.

I'm assuming that you know about anonymous nodes in RDF, but aren't
familiar with the Notation3 serialization. A "[]" is just an anonymous
node, q.v. [2]. You can give it a URI if you want. In fact, this would
have been useful for the XML Schema people to have defined the URIs
that they use to represent their QNames.

[...]
> The problem I am focusing on in my proposal is getting from
> RDF/XML instances to triples such that no matter what RDF parser
> you are using, so long as it conforms to the standard, you will
> get exactly the same set of triples with the exact same URIs
> for resources, [...]

Why? Why not just define them as anonymous nodes? You can say that a
combination of "ns" and "ExpEType/ExpAName" make for an unambiguous
subject using the following rule:-

   { { :x :ns :y; :expEType :z . :a :ns :y; expEType :z }
   log:implies
   { :x = :a } } a log:Truth; log:forAll :x , :y , :z , :a .

People simply aren't going to adopt "standard mappings". They want
flexible models.

> If one RDF parser gives you ns:name -> nsname and another
> gives you ns:name -> ns#name and yet another gives you
> ns:name -> 'ns'name (a'la SWI Prolog + RDF) and yet another
> gives you ns:name -> urn:qname:ns/name, etc. etc. [...]

Oh please! If the material being processed is indeed RDF, then the RDF
parser should only be expected to use the first form of resolution
from QName pair to URI. That's not the issue. The issue is how to
represent XML QNames in RDF, not how to process the XML Qnames that
are used to form the RDF. But yes, I agree with you very much that
this needs to be done somehow. It's useful to say that a certain
element in one language is the same as one in another language. But
you can do that using the anonymous node proposal above: no extra
syntax rubbish required.

> IMO it is the underlying conceptual model of triples that is the
> real value of RDF, and the serialization issues are entirely
> secondary. [...]

Once again, very much agreed.

> Furthermore, since humans need a means of easy data entry,
> and would prefer to enter 'en' for language rather than something
> like "http://some.authority.com/languages/English",

You have to declare a datatype in that case, but sure, why not?

   this xml:lang "en" .

I think there's an enumeration in XML Schema for those values
somewhere... it'd be cool if the W3C could post them in RDF using
DAML.

> and since we really want our SW Agents to deal with resources
> rather than literals as much as possible, we need to map the
> literal 'en' to the more informative and useful resource URI [...]

Huh? Just use datatypes; no need to complicate things. Go through the
DAML walkthrough (linked to from [3]).

Cheers,

[1] http://lists.w3.org/Archives/Public/www-rdf-interest/2001Jun/0216
[2] http://www.w3.org/2000/10/swap/Primer
[3] http://www.daml.org/2001/03/daml+oil-index

--
Kindest Regards,
Sean B. Palmer
@prefix : <http://webns.net/roughterms/> .
:Sean :hasHomepage <http://purl.org/net/sbp/> .
Received on Monday, 13 August 2001 19:49:29 GMT

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