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Re: RDF Recommendation Set comments (re agenda for 6th April)

From: fensel <dieter.fensel@ontotext.com>
Date: Thu, 07 Apr 2011 20:29:05 +0200
To: Pat Hayes <phayes@ihmc.us>,fensel <dieter.fensel@ontotext.com>
Cc: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>, "nathan@webr3.org" <nathan@webr3.org>,RDF WG <public-rdf-wg@w3.org>
Message-ID: <E1Q7u3P-0002vt-VK@lisa.w3.org>
Hi Pat,

sure. Everything you are writing is correct. However:

- I do not think that the problem of RDF is that it does not provide enough.
For a base layer were other languages are layered on top it provides actually
quite a lot of features. Bags, collections, and lists, reification, 
and statements
in the language over other language statements etc. Frankly, I think a better
job would have to keep RDF as simple and basic as possible. So I would
rather love to see a simplification than an enrichment of RDF.

- Why include stuff in the very base layer of the semantic web that you know
that other languages will forbid to keep inference tractable.

- Proper equality on the web is a fascinating research question and I expect
more and more PhDs on it. Currently its complexity is still mostly neglected or
"solved" very simplistic as in OWL. Again, I wonder whether a research issue
should already be standardized at the most basic level. Many people use
owl:sameAs because there is nothing better around for their purpose 
(similar SKOS
stuff comes without reasoning support). I do not think they are really happy
with it and calling it rdf:sameAs will not solve their problem either.

Dieter




At 18:22 06.04.2011, Pat Hayes wrote:

>On Apr 6, 2011, at 10:19 AM, fensel wrote:
>
> > At 13:39 06.04.2011, Pierre-Antoine Champin wrote:
> >> On 04/06/2011 05:14 AM, Pat Hayes wrote:
> >> > We might want to think about incorporating some version of sameAs
> >> > into RDFS, as this seems to be fundamental to linked data and also
> >> > widely misused. Having the real meaning of equality exposed in the
> >> > RDF standard itself might be doing the world a favor. (?)
> >>
> >> +1e99
> >
> > I think this may be a very bad idea. You would force all languages
> > layering on top of RDF to include equality.
>
>It depends what you mean by 'include'. A language based on RDF can 
>always declare that it will use some other term and refuse to accept 
>the RDF one, just as OWL uses owl:Thing rather than 
>rdf:Resource.  BUt it would be more useful and more in the spirit of 
>interoperability to use the same term and just acknowledge that it 
>is not using all the intended meaning of that term.
>
> > There are reasons
> > to prevent equality because it turns unification from a syntactical
> > operation into reasoning.
>
>Only if you claim to be logically complete. A reasoner can always 
>just ignore the equalities, or use them in a limited but useful way. 
>Reasoners are not *obliged* to squeeze every last drop of meaning 
>from all the RDF they encounter. Still, the RDF means what it means :-)
>
>Pat
>
> >
> > Dieter
> >
>
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Received on Thursday, 7 April 2011 18:35:42 GMT

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