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Re: literal value terminology (was: Re: Review of MT)

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Thu, 24 Jan 2002 13:44:20 +0000
Message-Id: <5.1.0.14.2.20020124134059.0386db90@joy.songbird.com>
To: Sergey Melnik <melnik@db.stanford.edu>
Cc: Pat Hayes <phayes@ai.uwf.edu>, Patrick Stickler <patrick.stickler@nokia.com>, w3c-rdfcore-wg@w3.org
At 06:21 PM 1/23/02 -0800, Sergey Melnik wrote:
> > PS. Let me try to review some of the issues. When discussing
> > datatypes, there is an established terminology used by XSD: lexical
> > spaces and value spaces. Sergey and I would both like to conform to
> > that as far as possible, to be sure. However I think that our
> > understandings of how to conform to it differ. My understanding
> > always was that the things in a datatype lexical space would be
> > identified with lexical items in RDF syntax, and things in the value
> > space would be identified with semantic values. (Hence the P-style
> > proposals, BTW, which try to incorporate the datatype mapping into
> > the MT as a special kind of interpretation mapping.) I think (?) that
> > Sergey's understanding is that the domains that arise in datatyping -
> > lexical spaces and value spaces - *both* belong in the semantics of
> > RDF, and that the lexical items in RDF syntax that refer to them are
> > something else altogether. Hence the 3-way distinction outlined
> > above, which distinguishes RDF syntax from datatype lexical space. I
> > can see how that would leave a terminological muddle surrounding the
> > term "literal value" , which sounds (to Patrick and Sergey?) like it
> > would be a (semantic) value which happened to be a literal, ie
> > something in the lexical space of a datatype. That interpretation
> > simply hadn't occurred to me, I confess.
>
>This is a perfectly accurate analysis, Pat, and a very nicely worded
>one. In fact, as obvious as it is, it did not occur to me that elements
>of lexical spaces (per XSD) could simply be identified with RDF literals
>(i.e. literal tokens ;)

Agreed...

>The question is whether we go with a 2-way or a 3-way distinction. It
>looks like this issue needs to be clarified in the "foundations" part of
>the datatyping document. The 3-way distinction seems somewhat more
>general. Are there any caveats? Which one would you prefer?

My question, which may really be the same question, is that if we identify 
RDF literals with datatype lexicals, then do we not have to admit these 
into the domain of discourse?  I think I kind-of assumed all along that 
that was happening.

#g


------------------------------------------------------------
Graham Klyne                    MIMEsweeper Group
Strategic Research              <http://www.mimesweeper.com>
<Graham.Klyne@MIMEsweeper.com>
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Received on Thursday, 24 January 2002 09:08:54 EST

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