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Re: semantics status of RDF(S)

From: Sandro Hawke <sandro@w3.org>
Date: Sun, 01 Apr 2001 12:17:04 -0400
Message-Id: <200104011735.f31HZf724316@daniel.hawke.org>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-rdf-logic@w3.org
Peter F. Patel-Schneider wrote:
> There has recently been a discussion on the semantic problems with RDF.  
>
> I strongly agree with Pat Hayes's characterization of RDF (and RDFS) as
> based on a fundamentally flawed semantic model

I agree there's a flaw here.  I'm afraid it may be hard to really
address it while maintaining the desired quality of RDF as "universal"
and relatively independent of contentious design issues.

I'm going to go out on a limb here and propose a solution that I think
provides solid semantics without being unduly restrictive.  It's
simple: reduce the RDF model to binary relations stated with
locally-scoped terms which may be defined directly in English (not
indirectly as URIs attached to semantics by various standards bodies
and by application developers).

More formally, in prolog syntax, the RDF model would be defined as
having two relations:
 
   binary_relation(subject_term, relation_term, value_term).

which means that the relationship identified by the relation_term (by
the mechanism defined below) is truly held between some object
identified by the subject_term and some object identified by the
value_term, respectively.

The definitional grounding for the relation_term and optionally for
the other terms would be provided by:

   english_definition(term, "This is English text which defines something").

This approach allows semantics to be defined with arbitrary precision
for humans by allowing the inclusion of entire textbooks or legals
codes if necessary.  And it allows machine processing via the
crude-but-effective mechanism of exact matching of strings.  In
effect, English text strings become the unique-identifiers which
people are using in RDF today.

Technical objections to the size of the strings and the tedium of
including many strings in every message may be addressed with the
existing web and a text-inclusion mechanism which can be easily
defined using the above mechanism.  If even greater brevity is
required in some communications context, some standard relationships
can be defined (using the above mechanism) as being already in place
at the time of reception of a message.  One could chose to use RDF M&S
1.0 (with some stated or unstated additional interpretation) in this
manner.

   -- sandro
Received on Sunday, 1 April 2001 12:17:19 GMT

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