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

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Wed, 30 Jun 2010 16:49:47 -0400
Message-ID: <4C2BADEB.3070202@openlinksw.com>
To: Pat Hayes <phayes@ihmc.us>
CC: Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
Pat Hayes wrote:
>
> On Jun 30, 2010, at 1:30 PM, Kingsley Idehen wrote:
>
>> 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.
>>
>> IMHO an emphatic NO.
>>
>> RDF is about constructing structured descriptions where "Subjects" 
>> have Identifiers in the form of Name References (which may or many 
>> resolve to Structured Representations of Referents carried or borne 
>> by Descriptor Docs/Resources). An "Identifier" != Literal.
>
> What ARE you talking about? You sound like someone reciting doctrine.
>
> Literals in RDF are just as much 'identifiers' or 'names' as URIs are. 
> They identify their value, most clearly and emphatically. They denote 
> in exactly the same way that URIs denote. "23"^^xsd:number   is about 
> as good an identification of the number twenty-three as you are ever 
> likely to get in any notational system since ancient Babylonia.

Yes, but ancient Bablyonia != World Wide Web of Structured Linked Data, 
slightly different mediums with some shared characteristics :-)

The World Wide Web is becoming a Distributed DBMS (in my eyes). Thus, 
unambiguous naming matters.

Literal Subjects aren't a "show stopper" per se. (esp. for local RDF 
data). My gripe simply boils down to the nuisance factor introduced by 
data object name ambiguity in a distributed data object oriented realm 
such as the emerging Web of Linked Data.

What does ""23"^^xsd:number " mean to anyone in a global data space? I 
know the meaning of: 
<http://km.aifb.kit.edu/projects/numbers/web/n23#this>, based on the 
resource I deref at: <http://km.aifb.kit.edu/projects/numbers/web/n23>



Kingsley


>
> Pat Hayes
>
>>
>> If you are in a situation where you can't or don't want to mint an 
>> HTTP based Name, simply use a URN, it does the job.
>>
>>
>>>
>>> Best,
>>>
>>> Nathan
>>>
>>>
>>
>>
>> -- 
>>
>> Regards,
>>
>> Kingsley Idehen          President & CEO OpenLink Software     Web: 
>> http://www.openlinksw.com
>> Weblog: http://www.openlinksw.com/blog/~kidehen
>> Twitter/Identi.ca: kidehen
>>
>>
>>
>>
>>
>>
>
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>
>
>
>
>


-- 

Regards,

Kingsley Idehen	      
President & CEO 
OpenLink Software     
Web: http://www.openlinksw.com
Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca: kidehen 
Received on Wednesday, 30 June 2010 20:50:23 UTC

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