Re: rdf as a base for other languages

Brian McBride wrote:

>
> I'd like to focus on my main question though.  What are the relative
> merits of 'extending' RDF v designing a new language for
> expressing rules which operate on ground facts expressed in RDF.
>

The problem is the term 'ground fact' and the way it is equated with the
simple _presence_ of a triple in RDF. In so doing, RDF uses up what a _fact_
is. For example, a new language or an extension of RDF might wish to equate
a fact with an expression constructed of multiple triples e.g. a subgraph.
But RDF does not allow the assertion of a subgraph without asserting every
triple in the subgraph.
Hence what should be a simple construct:

(not (color sky blue))

becomes contorted. And this is for a simple expression. More complex
expressions become hopelessely contorted.

If RDF did not direct that a triple is and is always a fact, then other
languages with use RDF would be free to define what are and are not facts.

Jonathan Borden
The Open Healthcare Group
http://www.openhealth.org

Received on Monday, 4 June 2001 07:43:14 UTC