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Re: Error in current WG test cases?

From: Dave Reynolds <der@hplb.hpl.hp.com>
Date: Mon, 10 Nov 2003 13:24:57 +0000
Message-ID: <3FAF91A9.30408@hplb.hpl.hp.com>
To: pat hayes <phayes@ihmc.us>
Cc: w3c-rdfcore-wg@w3.org, Jeremy Carroll <jjc@hplb.hpl.hp.com>, "Brian McBride (E-mail)" <bwm@hplb.hpl.hp.com>

pat hayes wrote:

>> In a message on 25th July [1] I noted that the tests:
>>   rdfms-seq-representation/Manifest.rdf#test002
>>   rdfms-seq-representation/Manifest.rdf#test004
>> appeared to be incorrect.
> 
> 
> No, they are correct. 

The RDFCore message thread [2] responding to my previous reporting of this 
seemed to indicate otherwise, I guess I misunderstood or something has changed.

> The stuff mentioned in the conclusion doesnt have 
> to be mentioned in the assumption.  However, it is fine for a FORWARD 
> rule-based reasoner not to generate all valid conclusions from an empty 
> graph, just as it would make sense not to generate everything from a 
> contradiction. But think of a query-responding engine that is given the 
> conclusion as a query: it could just say YES without even bothering to 
> check into its KB.

We're not using a (purely) forward rule-based reasoner, we are running the 
tests via a query interface, and would have no problem implementing it, if 
that is the correct thing to do.

My reading of the LC2 working drafts (not the editor's draft) is that a 
query to an empty model of the form:

   * rdf:type rdfs:ContainerMembershipProperty

should return empty, due to the restriction of the rdfs axioms to the 
vocabulary {V U crdfV U rdfsV}. Is that right (again in the LC docs not the 
editor's draft)?

I guess this would be framed as a negative entailment test of the form:

    "does the empty graph entail the graph:
    _:a rdf:type rdfs:ContainerMembershipProperty ."

If this understanding is right then that is why I felt the vocabulary in 
the conclusion does have to be mentioned in the assumptions. It would be 
rather inconvenient if a query of this form returned empty but a query for 
a specific rdf:_1 property returns a match.

I guess all this is now moot. I see from [3] that the semantics document 
has changed to drop the crdfV restriction so the above wildcard query 
should return an infinite set of matches. Is that correct?

This seems like quite a big post-LC2 change.

Dave

[2] http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jul/0324.html
[3] http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Nov/0041.html
Received on Monday, 10 November 2003 08:25:11 EST

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