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Re: PROV-ISSUE-7 (define-derivation): Definition for Concept 'Derivation' [Provenance Terminology]

From: Graham Klyne <GK@ninebynine.org>
Date: Thu, 02 Jun 2011 12:25:57 +0100
Message-ID: <4DE77345.4050509@ninebynine.org>
To: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
CC: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, public-prov-wg@w3.org
Khalid,

I agree that many of the examples of derivation we have raised relate to 
resource states.  But if, as has been suggested by myself and others, resource 
states are themselves resources (especially when named for the purposes of 
expressing a derivation), then such derivations can equally be regarded as 
relating resources.  I think that's more a difference of terminology than 
fundamental.

Where I think I may diverge from what you say is that I would not limit such 
expressions of derivation to resources that happen to be a state (or snapshot of 
state) of some resource.  I think defining that distinction in a hard-and-fast 
way, that also aligns with various intuitions we may have about derivation, may 
prove difficult to achieve (e.g. as I think is suggested by Jim Meyers in 
http://lists.w3.org/Archives/Public/public-prov-wg/2011Jun/0015.html (*)).

#g
--

(*) I just love the W3C mailing list archives - so easy to find links to 
messages, and thus capture provenance!

Khalid Belhajjame wrote:
> 
> Hi,
> 
>  From the discussion so far on derivation it seems that most people tend 
> to define derivation between resource states or resources state 
> representations, but not for resources.
> 
> My take on this is that in a context where a resource is mutable, 
> derivations will mainly be used to associate resource states and 
> resource states representations.
> 
> That said, based on derivations connecting resource states and resources 
> state representations, one can infer new derivations between resources. 
> For example, consider the resource r_1 and the associated resource state 
> r_1_s, and consider that r_1_s was used to construct a new resource 
> state r_2_s, actually the first state, of the resource r2. We can state 
> that r_2_s is derived from r_1_s, i.e., r_1_s -> r_2_s. We can also 
> state that the resource r_2 is derived from the resource r_1, i.e., r_1 
> -> r_2
> 
> PS: I added a defintiion of derivation within this lines to the wiki:
> http://www.w3.org/2011/prov/wiki/ConceptDerivation
> 
> Thanks, khalid
> 
> 
> 
> 
> On 01/06/2011 07:49, Luc Moreau wrote:
>> Hi Graham,
>>
>> Isn't it that you used the duri scheme to name the two resource states 
>> that exist in
>> this scenario?
>>
>> In your view of the web, is there a notion of stateful resource? Does 
>> it apply here?
>>
>> Thanks,
>> Luc
>>
>>
>>
>> On 31/05/11 23:57, Graham Klyne wrote:
>>> Luc Moreau wrote:
>>>> Graham,
>>>>
>>>> In my example, I really mean for the two versions of the chart to be 
>>>> available at
>>>> the same URI. (So, definitely, an uncool URI!)
>>>>
>>>> In that case, there is a *single* resource, but it is stateful. 
>>>> Hence, there
>>>> are two *resource states*, one generated using (stats2), and the 
>>>> other using (stats3).
>>>
>>> Luc,
>>>
>>> I had interpreted your scenario as using a common URI as you explain.
>>>
>>> But there are still several resources here, but they are not all 
>>> exposed on the web or assigned URIs.  I'm appealing here to anything 
>>> that *might* be identified as opposed to things that actually are 
>>> assigned URIs.   (For example, the proposed duri: scheme might be 
>>> used - http://tools.ietf.org/id/draft-masinter-dated-uri-07.html)
>>>
>>> (And the URI is perfectly "cool" if it is specifically intended to 
>>> denote a dynamic resource.  A URI used to access the current weather 
>>> in London can be stable if properly managed.)
>>>
>>> (I think this is all entirely consistent with my earlier stated 
>>> positions.)
>>>
>>> #g
>>> -- 
>>>
>>>> Of course, if blogger had used cool uris, then, c2s2 and c2s3 would 
>>>> be different resources.
>>>>
>>>> Luc
>>>>
>>>> On 05/31/2011 02:25 PM, Graham Klyne wrote:
>>>>> I see (at least) two resources associated with (c2):  one generated 
>>>>> using (stats2), and other using (stats3).  We might call these 
>>>>> (c2s2) and (c2s3). 
>>>>
>>
>>
> 
Received on Thursday, 2 June 2011 11:27:35 GMT

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