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RE: Comments on RDF Concepts and Abstract Data Model

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Fri, 22 Nov 2002 12:09:00 +0100
To: "Brian McBride" <bwm@hplb.hpl.hp.com>, "Jeremy Carroll" <jjc@hplb.hpl.hp.com>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: <phayes@ai.uwf.edu>, <www-rdf-comments@w3.org>
Message-ID: <BHEGLCKMOHGLGNOKPGHDMELNCAAA.jjc@hpl.hp.com>

It's saying read the semantics document!

Hmmm ...

I'll try explaining in more words what I think could be said, and then try
and put it back together.

Peter's basic obejction is that the emphasis on equality in the abstract
syntax is misleading because, what people really need to know is when two
expressions mean the same thing, not whether they are written in the same
way.

The treatment  in the abstract syntax inevitably only addresses being
written in the same way (the key expressions being typed literals and
graphs).

A different way of writing the note would be at the end of the section 4.

[[
NOTE: In application contexts, comparing the values of typed literals (see
4.5.2)
is usually more helpful than comparing their syntactic forms (see 4.5.1).
Similarly, for comparing RDF Graphs,
semantic notions of entailment (see RDF_SEMANTICS) are usually
more helpful than syntactic equality (see 4.3).
]]

I have heard other editors wanting to retain the definitions of equality,
and note that the emphasis of the WG's work as a whole has been more on the
semantics than the syntax; and this is reflected in the overall publication
(but not the concepts doc by itself).

Jeremy



> >Peter,
> >
> >I believe I have now understood your concerns on equality ...
> >
> >Would the following text near the beginning of the abstract
> syntax section
> >help (help enough to reduce it to a minor concern?)
> >[[
> >Note: Syntactic equality, between RDF graphs, URI references or
> literals,
> >is often inappropriate for applications. Semantic notions, defined in
> >[RDF-SEMANTICS], such as that of entailment between graphs, or that of
> >having the same denotation are usually preferable.
> >]]
>
> I'm concerned that this text is a little formidable for the intended
> audience of the concepts doc.
>
> I don't understand what it is trying to say.  Please remember that the
> intended audience of the concepts doc includes folks who are not
> mathematicians.  Please make the text accessible to them.
>
> Brian
>
>
Received on Friday, 22 November 2002 06:09:15 GMT

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