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Re: What do the ontologists want

From: Sandro Hawke <sandro@w3.org>
Date: Fri, 18 May 2001 06:47:36 -0400
Message-Id: <200105181047.GAA03586@hawke.org>
To: Peter Crowther <peter.crowther@networkinference.com>
cc: "'Sergey Melnik'" <melnik@db.stanford.edu>, www-rdf-logic@w3.org
> Ditch RDF and layer a logic directly on XML?  Just a thought... the problem
> is that it loses a lot of the work currently being put into the Semantic Web
> and being described using RDF, unless there's a well-defined migration path.
> But it would give much more flexible structures and a far simpler way of
> denoting what has formally defined semantics versus what is simply a data
> structure.

I think that's RuleML (http://www.dfki.uni-kl.de/ruleml/).  They're
trying to build logical expressions of various levels of
expressiveness on XML.

It might help explain RDF to say

  <rdf:Description about="Aristotle">
     <rdf:type rdf:resource="man" />
  </rdf:Description>

means exactly the same thing as

  <rule>
    <!-- no premise, this is a ground fact -->
    <conclusion>
      <constant>Aristotle</constant>
      <constant>http://www.w3.org/1999/02/22-rdf-syntax-ns#type</constant>
      <constant>man</constant>
    </conclusion>
  </rule>

give or take some conventions about string literals, namespaces, and
ordering of elements in a tuple (and the fact that I'm just guessing
at RuleML's current syntax -- sorry guys).

> The alternative appears to be to accept that RDF will be used as a very,
> very verbose encoding of LISP cons cells; and that some part of those
> structures might be used to represent something formal, but that a large
> part will straight data structure, or be glue that could be encoded and
> processed more easily using a richer syntax.

Basically yes, but two quibles:

1.  I think you over-estimate the fraction of the data in the universe
    that is more than ground facts.

2.  RDF is not necessarily verbose: the RDF syntax in the current W3C
    spec is verbose, but other RDF syntaxes are much less so (eg n3,
    as Jos de Roo pointed out).

      -- sandro
Received on Friday, 18 May 2001 06:47:49 UTC

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