W3C home > Mailing lists > Public > public-lod@w3.org > June 2010

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

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 30 Jun 2010 14:14:00 -0500
Cc: nathan@webr3.org, 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: <6C5707D3-4866-4E96-B054-92A2B2DDE05D@ihmc.us>
To: Kingsley Idehen <kidehen@openlinksw.com>

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.

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
>
>
>
>
>
>

------------------------------------------------------------
IHMC                                     (850)434 8903 or (650)494 3973
40 South Alcaniz St.           (850)202 4416   office
Pensacola                            (850)202 4440   fax
FL 32502                              (850)291 0667   mobile
phayesAT-SIGNihmc.us       http://www.ihmc.us/users/phayes
Received on Wednesday, 30 June 2010 19:16:24 UTC

This archive was generated by hypermail 2.3.1 : Sunday, 31 March 2013 14:24:27 UTC