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Re: Question about literals in subject position

From: Paul Gearon <gearon@ieee.org>
Date: Tue, 29 Sep 2009 09:49:53 -0400
Message-ID: <a25ac1f0909290649w5f5b8ee8h1d00fecf6bf4bf24@mail.gmail.com>
To: Ivan Herman <ivan@w3.org>
Cc: Birte Glimm <birte.glimm@comlab.ox.ac.uk>, "public-rdf-dawg@w3.org Group" <public-rdf-dawg@w3.org>
On Tue, Sep 29, 2009 at 3:47 AM, Ivan Herman <ivan@w3.org> wrote:
>
> Paul Gearon wrote:
>> On Mon, Sep 28, 2009 at 9:49 AM, Birte Glimm
>> <birte.glimm@comlab.ox.ac.uk> wrote:
>>> [snip]
>>>
>>>> We could change the definition to allow literals as subjects - in order to maintain compatibility absolutely with the Query 1.0 spec, the restriction could be moved into the definition of simple entailment matching, freeing it up for other entailment regimes.
>>>>
>>>> Query 1.0 notes that the RDF WG knew of no reason not permit them except the syntax issues with RDF/XML.
>>
>> I can't recall where I saw this, but didn't the RDF folks consider
>> adding them in if a new version of RDF ever happens?
>
> This is certainly one of the issues that a new RDF group would have to
> look at.
>
> _However_, and obviously putting the SemWeb Activity Head's hat on, it
> is not clear at all in my mind that re-opening an RDF group would be a
> good thing. RDF is at the centre of Semantic Web technologies, and
> reopening the group _may_ send out a message of instability that the
> market does not need. After all, it is only recently that we see this
> market to become more stabilized and prospering. (And, yes, I am torn on
> this issue and I know there will be disagreement on this...)
>
> We certainly should not expect any change on this subject during the
> lifetime of this group.

While I see the benefits of updating some aspects of RDF, I'm in
complete agreement with your position here. I was speaking more to the
mindset of the RDF designers, in that literal subjects aren't
completely evil and that they may even be considered useful in some
contexts.

Thinking this way is why I suggest that SPARQL need not make any
notion of literal subjects completely illegal. If they're allowed,
then they work perfectly with RDF as it stands. Even if allowing
literal subjects (especially through variable bindings) disagrees with
SPARQL 1.0, I don't believe it does so in a way that would impact any
existing systems. Indeed, some systems explicitly ignore the spec in
this regard.

Paul
Received on Tuesday, 29 September 2009 13:58:46 GMT

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