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

From: Haijie.Peng <haijie.peng@gmail.com>
Date: Sat, 03 Jul 2010 12:12:38 +0800
Message-ID: <4C2EB8B6.6060805@gmail.com>
To: Kingsley Idehen <kidehen@openlinksw.com>
CC: Pat Hayes <phayes@ihmc.us>, Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
On 2010/7/1 22:42, Kingsley Idehen wrote:
> Pat Hayes wrote:
>>
>> On Jun 30, 2010, at 3:49 PM, Kingsley Idehen wrote:
>>
>>> 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.
>>
>> A topic for a longer discussion; but irrelevant here, since typed 
>> literals are as unambiguous as a name can possibly get.
>>
>>>
>>> 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?
>>
>> It means the number twenty-three, everywhere and for all time, 
>> because this meaning can be computed from the very syntactic form of 
>> the name. How unambiguous can something get?
>
> Pat,
>
> Re. RDF's triples, What is a Subject? What is an Object?.
>
> If they are the same thing, why on earth do we use Names (with 
> implications) to describe the slots in an RDF triple?
>
> I've only once seen the RDF triple referred to as O-R-O (by @danbri) 
> i.e., Object-Relation-Object.
>
> In addition, I don't see Information and Data as being the same thing. 
> Information (as I know it) is about Data + Context.  Raw Data (as I 
> know it) is about: a unit of observation and deemed worthy of 
> description by its observer.  You have to give Names to subject of a 
> description. "23"^^xsd:number  isn't a Name.
>
> **
> I guess my own subtle mistake (re. this thread) is deeming Identifiers 
> and Names to be equivalent , when they aren't :-) Of course, one can 
> use an Identifier as a Name, but that doesn't make them equivalent.
> **
>
>
> One clear point of divergence here is that I am focused on the Web as 
> Dist. DBMS that leverages 3-tuples + HTTP URIs in the S, P, and 
> optionally O slot (aka. HTTP based Linked Data).
>
> To conclude:
>
> Name != Identifier.
We can also question the role of URI. Because the location of resource 
pointed by URI and the content of URI are orthogonal. A location is 
interpreted by a set of  locating operations, the locating result is 
only GUIDED, not CONTROLLED, by the content of URI. To realize this is 
very important!

regards

      Peng

>
> I believe Subject == Name (an Identifier based Name) re. RDF triples 
> otherwise the triple should be described as: O-R-O or O-P-O.
>
> I believe an S-P-O triple is a piece of information (Data Object has a 
> Name and at least one Attribute=Value pair).
>
> What I desscribe actually has zilch to do with RDF as I am inclined to 
> believe you see RDF :-) Thus, in a way, the literal-subject debate may 
> simply help everyone understand and accept that RDF != Linked Data. 
> Thus, providing additional proof that RDF isn't mandatory or even 
> required re. delivery of  HTTP based Linked Data.
>
> RDF based Linked Data != RDF. They are different things, clearly.  We 
> can't have it both ways (** Pat: not for you, that's for those that 
> deem RDF and Linked Data inextricably linked **).
>
>
> BTW - I still have no idea if RDF and RDF/XML are really distinct. 
> HTML and N3 built the Web of Linked Data, but N3  remains a 2nd or 3rd 
> class citizen whenever we talk about the pragmatic aspects of what 
> continues to be inappropriately labeled as an RDF virtue i.e. Linked 
> Data.
>
> Danbri:
>
> I agree with the essence of your earlier post!
>
>
> Kingsley
>
>
>>
>> Pat
>>
>>
>>> 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
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>> ------------------------------------------------------------
>>>> 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
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>> -- 
>>>
>>> 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 Saturday, 3 July 2010 04:13:21 UTC

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