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

On 06/30/2010 09:09 PM, Pat Hayes wrote:
> 
> 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.

I wonder, when using owl:sameAs or related, to "name" literals to be
able to say other useful thing about them in normal triples (datatype,
language, etc) does it break OWL DL (or any other formalism which is
base of some ontology extending RDF semantics)? Or would it if
rdf:sameAs was introduced?

Best,
Jiri

> 
> The Description Logic police are still in charge:-)
> 
> Pat
> 
> 
> 
>>
>> Best,
>>
>> Nathan
>>
>>
> 
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