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Re: Subjects as Literals, [was Re: The Ordered List Ontology]

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 30 Jun 2010 14:09:22 -0500
Cc: Toby Inkster <tai@g5n.co.uk>, Dan Brickley <danbri@danbri.org>, Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
Message-Id: <B230310F-C5F7-42EE-9043-09002E073268@ihmc.us>
To: nathan@webr3.org

On Jun 30, 2010, at 11:50 AM, Nathan wrote:

> Pat Hayes wrote:
>> On Jun 30, 2010, at 6:45 AM, Toby Inkster wrote:
>>> On Wed, 30 Jun 2010 10:54:20 +0100
>>> Dan Brickley <danbri@danbri.org> wrote:
>>>> That said, i'm sure sameAs and differentIndividual (or however it  
>>>> is
>>>> called) claims could probably make a mess, if added or removed...
>>>
>>> You can create some pretty awesome messes even without OWL:
>>>
>>>    # An rdf:List that loops around...
>>>
>>>    <#mylist> a rdf:List ;
>>>        rdf:first <#Alice> ;
>>>        rdf:next <#mylist> .
>>>
>>>    # A looping, branching mess...
>>>
>>>    <#anotherlist> a rdf:List ;
>>>        rdf:first <#anotherlist> ;
>>>        rdf:next <#anotherlist> .
>>>
>> They might be messy, but they are *possible* structures using  
>> pointers, which is what the RDF vocabulary describes.  Its just  
>> about impossible to guarantee that messes can't happen when all you  
>> are doing is describing structures in an open-world setting. But I  
>> think the cure is to stop thinking that possible-messes are a  
>> problem to be solved. So, there is dung in the road. Walk round it.
>
> Could we also apply that to the 'subjects as literals' general  
> discussion that's going on then?
>
> For example I've heard people saying that it encourages bad 'linked  
> data' practise by using examples like { 'London' a x:Place } -  
> whereas I'd immediately counter with { x:London a 'Place' }.
>
> Surely all of the subjects as literals arguments can be countered  
> with 'walk round it', and further good practise could be aided by a  
> few simple notes on best practise for linked data etc.

I wholly agree. Allowing literals in subject position in RDF is a no- 
brainer. (BTW, it would also immediately solve the 'bugs in the RDF  
rules' problem.) These arguments against it are nonsensical. The REAL  
argument against it is that it will mess up OWL-DL, or at any rate it  
*might* mess up OWL-DL.

The Description Logic police are still in charge:-)

Pat



>
> Best,
>
> Nathan
>
>

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Received on Wednesday, 30 June 2010 19:10:46 GMT

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