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KR and RDF (was RE: subclasses (RDF vocabulary definitions))

From: Jon Hanna <jon@spin.ie>
Date: Fri, 22 Nov 2002 14:46:45 -0000
To: <www-rdf-interest@w3.org>

> 4. If you compare KR and RDFS, I think you will find that
> a KR description is 10 times shorter and 10 times easier
> to read.

Easier to read for whom?

I think this is were KR and RDF will differ, and probably should differ.

If I understand correctly (I haven't had time to play with KR yet) KR is
designed explicitly to be reasonably close to English, and hence
understandable to human readers. RDF is designed to define relationships
between resources (referred to by URIs, though applications are as likely to
use 32-bit numbers internally) that is easy for machines to use.

While human-readability has been a feature of the design of URIs, and of the
various ways we express RDF (n-triples, RDF/XML, graphs in the sense of
actual pictures) it is of secondary import to RDF.

Neither of these makes one better than the other, but it does make one
better than the other for certain tasks.

> P.S. One of the things that makes RDFS more verbose is the
> multiple layers of definition, which then require qualifiers
> to distinguish the names, e.g.: rdfs:Class instead of Class.
> The OWL level should be the starting point, and should be the
> default with no qualifiers required for its names.  That's my
> practical advice for language design.

That's verbosity of particular forms of expression, not of RDF itself. In
RDF rdfs:Class is a shorthand for
http://www.w3.org/2000/01/rdf-schema#Class. In turn that URI identifies a
resource (the concept of Class as defined in RDFS). This being the web URIs
identify absolutely everything. Remember RDF isn't a language per se. It is
a framework for statements concerning triples of web resources that we use
different languages (RDF/XML, n3, diagrams, and a bastardised pseudo-n3
common in discussions on this list and elsewhere) to express.

The rdfs: in rdfs:Class is just a convention. Where appropriate you can use
Class, s:Class or nowImJustBeingSilly:Class. Whether OWL, RDF, RDFS or a
completely differnt level is the most natural "starting point" varies from
case to case.
Received on Friday, 22 November 2002 09:40:04 UTC

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