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Re: proposal to close Issue 5.8 Datatypes

From: Dan Connolly <connolly@w3.org>
Date: 25 Nov 2002 15:57:23 -0600
To: "Peter F. "Patel-Schneider <pfps@research.bell-labs.com>
Cc: www-webont-wg@w3.org
Message-Id: <1038261444.5319.432.camel@dirk>

On Thu, 2002-11-21 at 19:12, Peter F. Patel-Schneider wrote:
> I propose that we close issue 5.8 with the following resolution(s):
> 1/ The exchange syntax for OWL will use RDF datatyping.

I'm not sure what it means to agree to that.

I suppose that "RDF datatyping" refers to something like

but I'm not sure how this would show up in our
ref/guide/semantics specs.

> 2/ The abstract syntax for OWL will use <datatype><lexical> as the syntax
>    for typed data values and will only allow lexical forms that are valid
>    for the datatype, i.e., <xd:integer>1.5 is not a valid typed literal in
>    the abstract syntax.

It seems more clear to refer to the abstract syntax
as being for OWL DL, since it's not a syntax
for all of OWL.

> 3/ OWL will include all XML Schema built-in non-list simple types, using the
>    canonical URI reference for them.

I'm not sure what it means for OWL to include a type.
And I'm not sure why this is in the list in
addtion to 1/.

> 4/ OWL can use XML Schema non-list simple types defined at the top
>    level of an XML Schema document and given a name, by using the URI
>    reference constructed from the URI of the document and the local name of
>    the simple type.  That is, if U is the URI of an XML Schema document
>    that contains, 
>    <xsd:schema ...>
>      <xsd:simpleType name="foo">
>        <xsd:restriction base="integer">
>         <xsd:minInclusive value="1700">
>        </xsd:restriction>
>      </xsd:simpleType>
>      ...
>    </xsd:schema>
>    then the URI reference U#foo will be that datatype.

Hmm... it doesn't seem reasonable for our spec to say what
somebody else's URIref means. I'm not sure how to state
my objection clearly, since of course we can use OWL
to express constraints on the meaning of somebody
else's URIs...

But the form of specification you used doesn't work...
"if U is the URI of an XML schema document" is
an ill-formed definite description; there isn't
a well-defined mapping from XML Schema documents
to URIs.

>    Implementations of OWL may choose to ignore the facets such a type.

I don't know what it means to agree to that either.

> 5/ Cardinality restrictions in the exchange syntax for OWL will use typed
>    literals, as in 
>              _:x rdf:type owl:Restriction .
>              _:x owl:onProperty ex:foo .
>              _:x owl:cardinality "5"^^xsd:decimal . 
> The semantics document has been updated to reflect all this,

If you could refer me to specific text, I'd appreciate it.

> but some
> changes probably need to be made to the other documents.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Monday, 25 November 2002 16:57:24 UTC

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