W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > August 2001

doc1.rdf instance of doc2.rdf? SWAD requirement

From: Dan Connolly <connolly@w3.org>
Date: Wed, 15 Aug 2001 12:27:33 -0500
Message-ID: <3B7AB105.8AD520F6@w3.org>
To: w3c-rdfcore-wg@w3.org
We had a Semantic Web Advanced development discussion
about the issue

I argued earlier that if RDF is to be used to express
queries, then Prince nodes must be interpreted ala
	(exists (?x) (P ?x o))

Recall from Pat's ftf presentation[1] that indeed,
if RDF is to be used to express queries, the difference
between (exists (?x) ...) and a skolem-constant (aka genid)

But we didn't agree that RDF 1.0 was designed to express queries.

But from Pat's presentation, it became clear that *any*
use of RDF that puts a document "on the pointy end of
an entailment arrow" motivates the distinction between
existentially quantified variables and genids.
i.e. if we want to be able to ask

	Does rdf doc1 ential rdf doc2?

Then we need a model theory with existential quanitification.

In Semantic Web Advanced development, this is indeed
the case. We need the ability not only to say

	What are the triples in this document?

but also

	Does  doc1.rdf entail doc2.rdf?

witness EricM's recent workflow demo
which relies on TimBL's implementation of the relationship
Pat called "instance of"; in TimBL's code (and hence
in Eric's stuff) it's called log:includes.

There's a pile of test cases in

[I intended to produce a handful of test cases
that don't involve any N3-isms (contexts etc.);
just doc1.rdf and doc2.rdf where doc1 is or
isn't an instance of doc2. But I spent so much
time looking for meeting materials that aren't
there that I've got to get onto other stuff just

[1] I can't find it online. grumble.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Wednesday, 15 August 2001 13:27:34 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 20:24:03 UTC