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From: Sean B. Palmer <sean@mysterylights.com>
Date: Sat, 14 Jul 2001 01:18:32 +0100
Message-ID: <045301c10bfb$94661760$dde693c3@z5n9x1>
To: <w3c-wai-er-ig@w3.org>
> I got to page 7 of that article.  Way over my head at
> this point.

It goes nuts for me at page 14. Page 9 is the cool part.

> What I got out of it is that there is a "layer problem" which
> I'm not exactly sure what that means but that it originates
> with RDFS and is therefore carried on in DAML+OIL (since
> it builds on RDFS).

Yep. The layer problem is just that properties are being used for
several different functions in RDFS, and are therefore ambiguous.
Because logical systems require strict semantics, this ambiguity makes
it difficult for people to build stuff on top of RDFS. We even had
this problem a little bit in EARL - we use multiple ranges for
restrictions and so forth, and these are still being debated on RDF

There are some cool philisophical reasonsing about this sort of thing
at [1]. Just where is the design of EARL? Is it in the schema? In the
tutorials? In the implementations? It doesn't really matter as long as
it works, but it is an interesting debate.

> Do you  know if RDFS(FA) is being considered by the
> RDF groups?

I very much doubt it.

> Could you please explain the differences between the EARL
> schema expressed in RDFS versus RDFS(FA)?

The RDFS(FA) version is a refinement of the RDFS version. Or rather,
it will be when they publish more examples for reification and DAML; I
left that stuff out for now.

> Where do MStatements, LStatements, LClass, etc come
> from?  What does that mean?

They're just classes that have very specific functions in RDFS(FA).
Where we were previously using "ambiguous" classes, these are defined
more carefully. It is a matter of contention just how much more
"carefully" these classes are defined though.

> Also, I just realized that RDFS is a Candidate Recommendation - is
> that true?

Yep, that's true. It's been like that for some time now.

> I obviously don't know how this would fit in with the Abstract
> Syntax proposed by Jon Borden.

I'll be proposing another stripped-down syntax for RDF in XML soon.
Should make it easy to represent EARL in XML.

[1] http://c2.com/cgi/wiki?TheSourceCodeIsTheDesign

Kindest Regards,
Sean B. Palmer
@prefix : <http://webns.net/roughterms/> .
:Sean :hasHomepage <http://purl.org/net/sbp/> .
Received on Saturday, 14 July 2001 03:54:55 UTC

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