RE: Issue-104

Hi Alan!

Alan Ruttenberg wrote:

>I am confused as to it's status. The issue is whether there is a
>disallowed vocabulary. The notes have Michael saying there is, and I
>an thinks there is. This would suggest that closing the issue means
>saying that there is a disallowed vocabulary and a pointer to the
>appropriate place in the spec. However, I don't understand Peter's
>comment suggesting a break in backwards compatibility in this light.
>
>  I will review the current spec to find what Michael is referring
>to. However a summary of current understand so as to verify we're
>(including me) are all on the same page would help if someone happens
>to have the time to write.

To clarify: I mentioned in the last telco that there really is a disallowed
vocabulary in OWL 2 DL. It's in the Structural Spec [1], see table 1:

  "The URIs with namespaces rdf, rdfs, xsd, or owl 
  constitute the reserved vocabulary of OWL 2."

So the discussion was now more on whether the disallowed vocabulary is too
large or not.
 
Here are three points which I remember having said:

(1) I reported that I had once assembled a list [2] of vocabulary URIs,
which are *not* explicitly included in OWL 1 DL's disallowed vocabulary. At
that time, it seemed to (at least) Boris and me that most of the URIs in
that list were simply forgotten to be listed as disallowed vocabulary in OWL
1 DL, because there did not seem to be a clear reason why they were left
out.
 
(2) I pointed specifically to the RDF reification vocabulary, since this is
explicitly mentioned as an example for *not* being disallowed in OWL 1 DL,
see [3]. I noted that, if the WG decides to vote for the current solution,
where all of rdf: is disallowed, then this would also disallow the
reification vocabulary in OWL 2 DL. I said that this would technically be a
backwards compatibility issue, and the WG should at least be conscious of
this fact. (Personally, I am indifferent on this question.) 

(3) Someone mentioned that there might be a problem with having the complete
"xsd:" namespace in the table. I do not remember exactly what the reason
was. But I remember that I answered that we can, in principle, leave the
table as it is, and add explicit exception remarks if needed.

Hope this helps,
Michael

[1] <http://www.w3.org/2007/OWL/wiki/Syntax#URIs_and_Namespaces> 
[2] <http://lists.w3.org/Archives/Public/public-owl-wg/2008Jun/0044.html>
[3] <http://www.w3.org/TR/owl-semantics/mapping.html#4.2>

--
Dipl.-Inform. Michael Schneider
FZI Forschungszentrum Informatik Karlsruhe
Abtl. Information Process Engineering (IPE)
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