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Re: Fwd: OWL Test Cases and Species Validation

From: Sean Bechhofer <seanb@cs.man.ac.uk>
Date: Wed, 27 Aug 2003 09:48:52 +0100 (GMT Daylight Time)
To: Jim Hendler <hendler@cs.umd.edu>
Cc: webont <www-webont-wg@w3.org>
Message-ID: <Pine.WNT.4.44.0308270923400.4908-100000@potato>

On Tue, 26 Aug 2003, Jim Hendler wrote:

> I'm taking the liberty of forwarding this from the
> public-webont-comments list because it impacts CR exit criteria.  In
> particular, his first issue is an owl:imports case - and if he's
> wrong, we should make sure it is clear why in one of our documents
> (if one person gets it wrong, others might, and owl:imports was
> called out by the Director as something we need to pay attention to).
> Second one is Lite/DL issue.
>   Sean - can you check output of your species checker on these and let us know?
>   thanks
>   JH

> >>  1)
> >>
> >>  Test case:
> >>  http://www.w3.org/2002/03owlt/imports/Manifest001
> >>  Premise document:
> >>  http://www.w3.org/2002/03owlt/imports/premises001
> >>
> >>
> >>  In the manifest, the premise document is declared an OWL Full
> >>document.  When I first looked at the premise document, that seemed
> >>to be the correct species because ont:Man is used, but not defined,
> >>making it an OWL Full document.  But when you take into
> >>consideration the owl:imports statement in the file, you would
> >>merge the graph for that document with the imported document and
> >>the resulting graph would have the definition for ont:Man present
> >>making the premises001 file an OWL Lite document and not an OWL
> >>Full document.  Thus, I believe the species on the test case is
> >>incorrect and needs to be changed.

In the premises document, the triple:

<rdf:Description rdf:about=''>
 <owl:imports rdf:resource="http://www.w3.org/2002/03owlt/imports/support001-A"/>

uses owl:imports without explicitly saying that the URI to which it
applies is an owl:Ontology. Thus we are in Full.

> >>  2)
> >>
> >>  Test case:
> >>  http://www.w3.org/2002/03owlt/miscellaneous/Manifest102
> >>  Input document:
> >>  http://www.w3.org/2002/03owlt/miscellaneous/consistent102
> >>
> >>  The manifest declares the input as an OWL DL document.  In section
> >>8.3 of the OWL Web Ontology Language Reference (regarding use of
> >>owl:intersectionOf in OWL Lite documents) it says:
> >>
> >>  “owl:intersectionOf be used only on lists of length greater than
> >>one that contain only named classes and restrictions”
> >>
> >>  This would appear to be the case for the input document, the
> >>object of the owl:intersectionOf triple is a list of length greater
> >>than one containing only restrictions.  I think the input document
> >>is an OWL Lite document and the test case should be changed
> >>accordingly.

Section 4.1 of S&AS details the mapping rules that translate abstract
syntax to triples. Examination of the table shows that there are only
three ways in which an intersectionOf triple can occur:

1) Due to a class definition

	Class(classID [Deprecated] partial
      		annotation_1 ... annotation_m
		description_1 ... description_n)

2) Due to an intersectionOf expression

	intersectionOf(description_1 ... description_n)

3) Due to a restriction with multiple components:

	restriction(ID component_1 ... component_n)

Now 2) and 3) are only available in OWL DL (See Section 2.3 of S&AS). So
for an intersection to be valid in an OWL-Lite document, it must have come
from the translation of a class definition, and (from the right hand side
of the table in 4.1) it must therefore be the case that the subject of the
intersectionOf triple is a classID. This is *not* the case in
miscellaneous/consistent102, as the subject of the intersection is a blank
node. So the ontology is not Lite.

I guess the upshot of this is that the restriction listed in section 8.3
of Reference is not quite strong enough -- it is not only the case that
intersectionOf be used only on lists of length greater than one that
contain only named classes and restrictions -- in addition intersectionOf
cannot apply to blank nodes.



Sean Bechhofer
Received on Wednesday, 27 August 2003 04:54:42 UTC

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