W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > June 2001

Re: Abstract syntax: an attempt

From: pat hayes <phayes@ai.uwf.edu>
Date: Sat, 23 Jun 2001 23:22:15 -0500
Message-Id: <v0421010cb75a4d2ff19c@[]>
To: fmanola@mitre.org
Cc: w3c-rdfcore-wg@w3.org
>Sergey Melnik wrote:
> >
> > Brian,
> >
> > I'd just like to reiterate some of the arguments for making reification
> > a built-in feature (possibly as an optional layer):
> >
> > - in M&S, reified statements need to have a URI. It looks like they
> > should be unique, but nobody wants to deal with uniqueness, but still
> > some sort of URIs need to be assigned, so we end up having to deal with
> > different URIs denoting the same statement etc.
> >
> > - in M&S, we need a specific vocabulary to express/use reification.
> > Reification could be defined without relying on vocabularies.
> >
> > - as defined in M&S, reification is extremely verbose and clumsy both in
> > APIs and in the syntax, and very few people are using it as suggested.
> > However, I personally believe it is a useful feature when introduced
> > correctly and compactly, and it can be easily handled in APIs and
> > databases as an intrinsic model feature.
> >
> > Finally, (s1 p1 (s2 p2 o2)) looks nicer in the abstract syntax...
>I, for one, would find it easier to follow these discussions if we
>distinguished the "reification" that is currently defined in the M&S
>(which involves creating multiple triples, rather than nesting the
>triple that is to be reified) from alternative notations like (s1 p1 (s2
>p2 o2)).  I agree the latter is much nicer,

I agree. In fact if there was some way to 'nest' assertions in RDF, 
it would be a vastly different and greatly improved language. 
Unfortunately, as far as I can tell, that cannot be feasibly done 
within the confines of the basic RDF 1 model (ie without introducing 
some changes in the basic triples idea, such as N3's {'contexts'} ) 
other than by using something like RDF containers, which have exactly 
the verbose and clumsy translation that Sergey doesnt like. Drew 
McDermott and Jon Borden and I have been trying hard to do it, but we 
can't see how.

Pat Hayes

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Received on Monday, 25 June 2001 10:43:32 UTC

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