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RE: declaredAs

From: John McClure <jmcclure@hypergrove.com>
Date: Fri, 10 Aug 2007 12:29:51 -0700
To: "Bijan Parsia" <bparsia@cs.man.ac.uk>
Cc: "Owl Dev" <public-owl-dev@w3.org>
Message-ID: <MGEEIEEKKOMOLNHJAHMKGEINEFAA.jmcclure@hypergrove.com>

Bijan,
Some specific responses to your citation & other remarks:

>http://www.w3.org/TR/rdf-syntax-grammar/#section-Syntax-ID-xml-base
>
>"""RDF/XML allows further abbreviating RDF URI references in XML
>attributes in two ways.
>The rdf:ID attribute on a node element (not property element, that
>has another meaning) can be used instead of rdf:about and gives a
>relative RDF URI reference equivalent to # concatenated with the
>rdf:ID attribute value. So for example if rdf:ID="name", that would
>be equivalent to rdf:about="#name". rdf:ID provides an additional
>check since the same name can only appear once in the scope of an
>xml:base value (or document, if none is given), so is useful for
>defining a set of distinct, related terms relative to the same RDF
>URI reference."""

The spec specifically says that rdf:ID's semantic is overloaded .... a different
semantic in different contexts ... that's a real problem I am proposing should
be fixed. The second-to-last statement does NOT say that ID & about are
semantically equivalent; it says their subjects are pointing at the same
resource. Finally, the last sentence is clear to me, as it's refering to the
*functional role* of rdf:ID as an XML ID and is therefore not new information.
(I'm thinking I can't find an XML schema definition for ID because the spec
requires rdf:ID to functionally perform as an XML ID, but because it's a uri,
then it can't parse as a standard XML ID. Hmm, maybe there's a way around this
in xmls.)

>I agree that the last sentence is misleading and there are only a
>very limited number of cases where it can be made to work and
>requires otherwise restricting the syntax. And has no effect on the
>model.

You mean on the graph. That is where we differ, as I am saying that when the
Description is converted to a Statement then the effect of rdf:ID vs rdf:about
is clear, because the uri of an about Statement is a blank while the uri of an
ID Statement is the same as the subject's.

<snip/>

>> My thinking is that, to the contrary, a given document may
>> have only one declaration for a thing, but can have as many
>> assertions about it
>> as they care to have, so it's important to have both properties.
>
>In OWL 1.1 things can have many declarations per term.

Is the functional XML ID role for rdf:ID now being eliminated?

>I don't know  why only one is valuable.

Because declarations take precedence over assertions. A 'trust' thing.

>But rdf:ID doesn't get you *any sort of
>declaration*. It's *just a funny way of making an assertion*.

Nope, I don't agree -- I don't see this in the specs anywhere.
Received on Friday, 10 August 2007 19:29:31 UTC

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