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Re: ACTION-92

From: Graham Klyne <graham.klyne@zoo.ox.ac.uk>
Date: Fri, 22 Jun 2012 15:33:03 +0100
Message-ID: <4FE4821F.7030506@zoo.ox.ac.uk>
To: Luc Moreau <l.moreau@ecs.soton.ac.uk>
CC: Provenance Working Group WG <public-prov-wg@w3.org>
Luc,

I can't manage the detailed context(sic) of this discussion and example when it 
comes round every few days -- but I do believe that the contextualization 
relation is potentially dangerous.

As far as I can tell it has NO semantics that distinguish it from 
specializationOf, yet I believe it encourages users to read into it uses that 
could violate the semantics of RDF URI usage.

Thus, my immediate question is this.  What inferences are possible using 
contextualizationOf:

    A
    contextualizationOf(e1, e2, b)
|-
    B

that are not also valid inferences using specializationOf

    A
    specializationOf(e1, e2)
|-
    B

?

I can't see any.  In the absence of such, I can't see any valid reason for 
including contextualizationOf.  And in the absence of such, I can't see the 
formal basis for your (implied) claim that contextualizationOf does identify the 
bundle in which ex:Bob occurred.  I believe this is an area in which we really 
*need* formalization and rigour.

Part of the reason that I'm so wary of this particular relation is that I think 
it usurps a part of semantic web technology that is being defined by the RDF 
working group ("named graphs", datasets and associated semantics).  As such, I 
think the whole discussion about this should be conducted in the provenance+RDF 
coordination group.

#g
--


On 21/06/2012 13:43, Luc Moreau wrote:
> Hi Graham,
>
> It is on purpose that we didn't define context. In the WG there is a precedent
> of not defining
> terms. To name a few: thing, aspect, act upon/with, bear responsibility, goals,
> steps, assignment, ...
> So the word 'context' is to be understood with its informal meaning, .... like
> 'context' already
> used in the definition of association [1].
>
> As far as your response to Tim is concerned, of course, we
> can say that if
> tool:Bob_as_in_run1 prov:contextualizationOf ex:Bob
> then
> tool:Bob_as_in_run1 prov:specializationOf ex:Bob
> given that contextualizationOf is defined as a subproperty of specializationOf.
>
> But your solution fails to identify the bundle in which ex:Bob occurred, which
> led to the poor rating.
> Regards,
> Luc
>
> [1]
> http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-dm.html#concept-activityAssociation
>
>
> On 15/06/2012 16:32, Graham Klyne wrote:
>> This is my attempt to respond to ACTION-92.
>>
>> On 14/06/2012 23:07, Luc Moreau wrote:
>> > In your absence, we assigned ACTION-92 to you.
>> > Can you provide an example of contextualization you think
>> > may break rdf semantics?
>>
>> This is hard to do without a complete formal description of what
>> contextualization actually means.
>>
>> I did reply [1] to Tim's comment, and the reference to the example in the wiki.
>> I would adjust my earlier comment to say something like this: I cannot see
>> how contextualization can be anything but vacuous without violating RDF
>> semantics; i.e. how it actually expresses anything that cannot be expressed
>> without it.
>>
>> I've studied the description of contextualization in DM
>> (http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-dm.html#term-contextualization),
>>
>> and when I dig in to it I find I can't make any sense of what it is saying.
>>
>> As it stands, the notion of context is undefined, so I am unable to interpret
>> statements like "A bundle's descriptions provide a context in which to interpret
>> an entity in a domain-specific manner". What is this "context"? When I look to
>> the definition of "bundle", I see "A bundle is a named set of provenance
>> descriptions ...". There's nothing here about defining or providing a
>> "context". So this notion of context is being introduced without any grounding
>> or basis for understanding what it means.
>>
>> #g
>> --
>>
>> [1] http://lists.w3.org/Archives/Public/public-prov-wg/2012Jun/0310.html
>>
>>
>> On 14/06/2012 23:07, Luc Moreau wrote:
>>> Graham,
>>> In your absence, we assigned ACTION-92 to you.
>>> Can you provide an example of contextualization you think
>>> may break rdf semantics?
>>> Thanks,
>>> Luc
>>>
>>> PS. Tracker, this is ISSUE-385
>>>
>>> On 14/06/12 23:04, Luc Moreau wrote:
>>>> Dear all,
>>>>
>>>> Minutes of todays's teleconference can be found at
>>>> http://www.w3.org/2011/prov/meeting/2012-06-14
>>>> Thanks to Paolo for scribing.
>>>> Regards,
>>>> Luc
>
Received on Friday, 22 June 2012 15:31:27 UTC

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