Re: ldp-ISSUE-72 (membershipObject): The object of a membership triple isn't always the address of the created informational resource [Linked Data Platform core]

On 22 May 2013, at 15:43, Roger Menday <roger.menday@uk.fujitsu.com> wrote:

> 
>> Hi Roger, 
>> could you please post an example that illustrates what the problem is? I have to admit not to understand. 
> 
> There is lots of coverage around this in many of Henry's recent emails ... :) 
> 
> Anyway, I'll have a go at providing an example showing the problem. Picking up on the cat use-case that Henry introduced a few weeks ago:
> 
> There is an LDPR </people/roger>, this has a LDPC which is used to manage my pets. 
> 
> Let's say this LDPC has a membershipSubject of </people/roger> and membershipPredicate of pets:has_pet. If I POST the following to the LDPC: 
> 
> <> a animal:Cat; 
>     foaf:name "Zaza".
> 
> ... a new resource is created. 
> And there is a new membership triple of 
> 
> </people/roger> pets:has_pet </people/roger/zaza>
> 
> If one wants to keep the two resources separated, I might POST the following
> 
> <> foaf:primaryTopic <#this> .
> <#this> a animal:Cat;
>      foaf:name "Zaza". 
> 
> However, the new membership triple in this case is not quite right. It still is : 
> 
> </people/roger> pets:has_pet </people/roger/zaza>
> 
> ... but it should really be :
> 
> </people/roger> pets:has_pet </people/roger/zaza#this> 
> 
> That's the problem. 

Ok so presumably the problem here is that </people/roger> is a document too
so that you want the relation not to be on </people/roger> but on </people/roger#i>
right. And that is what the ldp:membershipSubject would be for....

So we would then have

<> a ldp:Container;
     ldp:membershipSubject <#i>;
     ldp:membershipOject ??? ;
     ldp:membershipPredicate pets:has_pet .

<#i> pets:has_pet <zaza#it>, <zara#it> .

so clearly here pets:has_pet has nothing to do with rdf:contains anymore.

Which proves my point that this membershipXXX is orthogonal to rdf:member-ships.
Hence we should seperate these two issues completely, and state that every 
POST to a LDPC adds a new rdf:member. 

The membershipXXX relations can be in addition to that. They are orthogonal.


> 
> Roger
> 
>> Thanks.
>> --
>> Arnaud  Le Hors - Software Standards Architect - IBM Software Group
>> 
>> 
>> 
>> 
>> From:        "Linked Data Platform (LDP) Working Group Issue Tracker" <sysbot+tracker@w3.org> 
>> To:        public-ldp-wg@w3.org, 
>> Date:        05/22/2013 02:13 AM 
>> Subject:        ldp-ISSUE-72 (membershipObject): The object of a membership triple isn't always the address of the created informational resource [Linked Data Platform core] 
>> 
>> 
>> 
>> ldp-ISSUE-72 (membershipObject): The object of a membership triple isn't always the address of the created informational resource [Linked Data Platform core]
>> 
>> http://www.w3.org/2012/ldp/track/issues/72
>> 
>> Raised by: Roger Menday
>> On product: Linked Data Platform core
>> 
>> When creating a new resource, the membershipPredicate and membershipSubject properties are used to construct a new triple expressing the relationship between the LDPR and the newly created resource. As pointed out by Henry, e.g. in [1], there is a current limitation because this new triple only references the document that contains the description (rather than the resource itself).
>> 
>> One solution might be :: when creating the membership triple, if the POSTed content includes a primaryTopic reference, the server should use that address as the object in the membership triple (and not that of the information resource itself). 
>> 
>> [1] http://lists.w3.org/Archives/Public/public-ldp-wg/2013May/0186.html
>> 
>> 
>> 
>> 
> 

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