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Re: reply to a POWDER Group request

From: Ivan Herman <ivan@w3.org>
Date: Wed, 15 Apr 2009 10:54:00 +0200
Message-ID: <49E5A0A8.4000102@w3.org>
To: Michael Schneider <schneid@fzi.de>
CC: public-owl-wg@w3.org

for the records, here is an updated answer draft. For the time being I
left the remark of referring to the OWL 2 Overview, I can remove that
item if the WG decides otherwise this evening. I have not made any
remark on XML Literals; as you say, that datatype is de facto part of
the OWL 2 RDF Based semantics, ie, the at-risk status would not affect
that. Finally, as I said the other day I would prefer not to comment on
their (informal) extension mechanism which is in line with what the
group does elsewhere.

Cheers and many thanks



Dear Phil,

thanks for you note. We have indeed found some problems in section 4.6
of http://www.w3.org/TR/2009/WD-powder-formal-20090403/ which needs
updates. There are as follows.

- The reference should be to XSD1.1 and not XSD2:

- 'At the time of writing, the OWL-2' should say "OWL 2" (ie, no hyphen)

- The reference to OWL 2 currently points to the OWL 2 primer. We think
it would be better if it pointed at the (new) OWL 2 Overview document:

- The semantic condition refers to rdfs:Resource for the domain of
hasIRI. Although the description refers to an extension of the RDF
semantics, it makes use of, say, owl:DatatypeProperty. Hence it may be
stylistically better to refer to owl:Thing.

- The encoding of the condition in the example has several problems,
partially due to some recent changes in OWL 2. These are

    - namespace changes (OWL 2 refers to xsd:pattern directly and not
owl:pattern; it reuses rdfs:Datatype instead of datarange)

    - we also think that the type of restriction used is inappropriate.
owl:hasValue should refer to a single individual and not to a
datatype/datarange. Based on the rest of the POWDER semantics, what you
probably have to use is owl:allValuesFrom, but this is something you
have to decide, of course

    - the RDF mapping of facets is based on a list of blank nodes
instead of the approach used in the current code

The first example (the second has similar structure) should look
something like:

  <owl:onProperty rdf:resource="....#hasIRI"/>
      <owl:onDatatype rdf:resource="...#string"/>
      <owl:withRestrictions rdf:parseType="Collection">
          <xsd:pattern rdf:datatype="...#string">PATTERN</xsd:pattern>

We are sorry not to have spotted this issue earlier.


(In the name of the OWL 2 Working Group)


Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
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Received on Wednesday, 15 April 2009 08:54:34 UTC

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