W3C home > Mailing lists > Public > semantic-web@w3.org > June 2010

Re: The Ordered List Ontology

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 30 Jun 2010 14:17:10 -0500
Cc: Toby Inkster <tai@g5n.co.uk>, Graham Klyne <GK@ninebynine.net>, Bob Ferris <zazi@elbklang.net>, Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
Message-Id: <D78208AE-0ABA-4381-B4FC-7112699399C5@ihmc.us>
To: Dan Brickley <danbri@danbri.org>

On Jun 30, 2010, at 1:15 PM, Dan Brickley wrote:

> On Wed, Jun 30, 2010 at 6:34 PM, Pat Hayes <phayes@ihmc.us> 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.
>
> Yes.
>
> So this is a point that probably needs careful presentation to new
> users of this technology. Educating people that they shouldn't believe
> any random RDF they find in the Web, ... now that is pretty easy.
> Still needs doing, but it shadows real world intuitions pretty well.
>
> If in real life you think the Daily Mail is full of nonsense, then it
> isn't a huge leap to treat RDFized representations of their claims
> with similar skepticism (eg. see
> http://data.totl.net/cancer_causes.rdf for a great list of Things The
> Daily Mail Say Might Cause Cancer).
>
> *However* it is going to be tough to persuade developers to treat a
> basic data structure like List in the same way.

Sure.  But what they need to grok is that RDF does not have ANY data  
structures in it (except maybe triples). It describes data structures,  
just like it describes everything else. It does not PROVIDE data  
structures. Maybe it should - make the case! - but then it will need  
to change rather drastically in its very foundation. Triples  
describing lists are not the same as triples-plus-lists.

Pat

> Lists are the kinds of
> thing we expect to be communicated perfectly or to get some low-level
> error. A lot of developers will write RDF-consuming code that won't
> anticipate errors. Hopefully supporting software libraries can take
> some of the strain here...
>
> cheers,
>
> Dan
>
>

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Received on Wednesday, 30 June 2010 19:18:18 GMT

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