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Re: Contextualization ---> Optional bundle in Specialization

From: Graham Klyne <Graham.Klyne@zoo.ox.ac.uk>
Date: Wed, 27 Jun 2012 23:57:24 +0100
Message-ID: <4FEB8FD4.3090705@zoo.ox.ac.uk>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
CC: Jim McCusker <mccusj@rpi.edu>, Paul Groth <p.t.groth@vu.nl>, Provenance Working Group WG <public-prov-wg@w3.org>
On 27/06/2012 22:21, Luc Moreau wrote:
> Hi Jim,
>
> ex:Bob refers to a single resource in this example.
> The interpretation of ex:Bob does not change according to the graph it occurs in.

Quite.  So what basis is there for claiming that two specializations of ex:Bob 
are somehow distinct, and that inferences that are true for one such 
specialization are not true for the other?

#g
--

> On 27/06/12 19:33, Jim McCusker wrote:
>> What Graham is objecting to (I think) is the idea that ex:Bob in one graph is
>> referring to something different from what ex:Bob is referring to in another
>> graph. That's not possible in RDF, as while we can have more than one symbol
>> (IRI) denote the same resource, it's by definition impossible for a symbol to
>> denote multiple resources in different contexts. The symbol is universally
>> scoped if it is an IRI. If it is not universally scoped, it needs to be
>> anonymous or skolemized.
>>
>> GK, correct me if I misunderstood.
>>
>> Jim
>>
>> On Wed, Jun 27, 2012 at 2:21 PM, Paul Groth <p.t.groth@vu.nl
>> <mailto:p.t.groth@vu.nl>> wrote:
>>
>> So the use case is the issue?
>>
>> I really don't get how the example breaks any semantics. Sorry...
>>
>> So I think that your approach to allowing a qualified
>> specialization would be fine with me especially if we add a
>> inBundle predicate that identifies a bundle. but Tim was really
>> really against this because of the increased number of triples.
>>
>> Paul
>>
>>
>> On Jun 27, 2012, at 19:48, Graham Klyne <graham.klyne@zoo.ox.ac.uk
>> <mailto:graham.klyne@zoo.ox.ac.uk>> wrote:
>>
>> > On 27/06/2012 18:39, Paul Groth wrote:
>> >> Hi Graham
>> >>
>> >> These are two different urls so they identify different things.
>> >
>> > Not necessarily, There is no unique-name assumption in RDF.
>> They could denote
>> > the same thing.
>> >
>> >> The fact that we add some properties like bundle or
>> specializationof doesn't break anything. I can do that with any
>> resource on the web, no?
>> >
>> > Adding the properties per se doesn't break anything, but when
>> they are presented
>> > as addressing a use-case that I don't believe can be addressed
>> by RDF semantics,
>> > they run the risk of encouraging people to creating RDF data
>> that doesn't mean
>> > what they think it means when interp[reted in accordance with
>> RDF semantics.
>> >
>> > #g
>> > --
>> >
>> >> Paul
>> >>
>> >> On Jun 27, 2012, at 19:09, Graham
>> Klyne<graham.klyne@zoo.ox.ac.uk
>> <mailto:graham.klyne@zoo.ox.ac.uk>> wrote:
>> >>
>> >>> On 27/06/2012 10:49, Luc Moreau wrote:
>> >>>> All,
>> >>>>
>> >>>> At the face to face meeting, we have agreed to rename
>> contextualization and mark
>> >>>> this feature
>> >>>> at risk. Tim, Stephan, Paul and I have worked a solution that
>> we now share with
>> >>>> the working group.
>> >>>
>> >>> I'm afraid I still have a problem with this.
>> >>>
>> >>> Considering your bundle tool:analysis01:
>> >>> [[
>> >>> bundle tool:analysis01
>> >>> agent(tool:Bob-2011-11-16, [perf:rating="good"])
>> >>> specializationOf(tool:Bob-2011-11-16, ex:Bob, ex:run1)
>> >>>
>> >>> agent(tool:Bob-2011-11-17, [perf:rating="bad"])
>> >>> specializationOf(tool:Bob-2011-11-17, ex:Bob, ex:run2)
>> >>> endBundle
>> >>> ]]
>> >>>
>> >>> The problem is that, if subject to RDF semantics for URI
>> interpretation, I can
>> >>> see no semantic distinction is possible between
>> >>>
>> >>> tool:Bob-2011-11-16
>> >>> and
>> >>> tool:Bob-2011-11-17
>> >>>
>> >>> I.e. they are both specializations of ex:Bob, and that is all
>> we can know about
>> >>> them, as (by the nature of the semantics of URI
>> interpretation) the denotation
>> >>> of ex:Bob that appears in ex:run1 is the same as the
>> denotation of ex:Bob that
>> >>> appears in ex:run2.
>> >>>
>> >>> ...
>> >>>
>> >>> I do, however, have a different compromise that provides a
>> hook for introducing
>> >>> possible semantics later, or in private implementations,
>> without sneaking in
>> >>> something that could well turn out to be incompatible with, or
>> just different
>> >>> than, what the RDF group may do for semantics of datasets.
>> >>>
>> >>> The hook is this: simply allow attributes for the
>> specializationOf relation, but
>> >>> don't define a specific attribute for bundle. This would
>> allow you to do a
>> >>> private implementation of the scheme you describe, but would
>> not allow it to be
>> >>> mistaken for something that has standardized semantics. As in:
>> >>>
>> >>> specializationOf(tool:Bob-2011-11-17, ex:Bob,
>> >>> [myprivateattribute:bundle=ex:run2])
>> >>>
>> >>> ...
>> >>>
>> >>> In case you think I'm jumping at shadows here, I'll note that
>> RDF has been here
>> >>> before. The original 1999 RDF specification described
>> reification without
>> >>> formal semantics. Reification was intended to allow for
>> capturing this kind of
>> >>> information - i.e. to make assertions about context of use,
>> etc - a kind of
>> >>> proto-provenance, if you like. But when the group came to
>> define a formal
>> >>> semantics for RDF, there were two possible, reasonable and
>> semantically
>> >>> incompatible approaches; looking at the way that reification
>> was being used "in
>> >>> the wild", it turned out that there was data out there that
>> corresponded to both
>> >>> of these (incompatible) approaches. This was in the very
>> early days of the
>> >>> semantic web, so the harm done was quite limited. I think a
>> similar mistake
>> >>> today would cause much greater harm.
>> >>>
>> >>> I think the appropriate way forward is to take this tool
>> performance analysis
>> >>> use-case to the RDF-PROV coordination group, and ask that it
>> be considered as
>> >>> input when defining semantics for RDF datasets. I would
>> expect that whatever
>> >>> semantic structure they choose, it should be able to
>> accommodate the use-case.
>> >>> Then, we should be better placed to create an appropriate and
>> compatible
>> >>> contextualization semantics for provenance bundles. But until
>> then, I think we
>> >>> invite problems by trying to create a standardized data model
>> structure without
>> >>> standardized RDF-compatible semantics to accommodate this
>> use-case.
>> >>>
>> >>> #g
>> >>> --
>> >>>
>> >>> Tracker, this is ISSUE-385
>> >>>
>> >>> On 27/06/2012 10:49, Luc Moreau wrote:
>> >>>> All,
>> >>>>
>> >>>> At the face to face meeting, we have agreed to rename
>> contextualization and mark
>> >>>> this feature
>> >>>> at risk. Tim, Stephan, Paul and I have worked a solution that
>> we now share with
>> >>>> the working group.
>> >>>>
>> >>>> Given that contextualization was already defined as a kind of
>> specialization, we
>> >>>> now allow an optional
>> >>>> bundle argument in the specialization relation. (Hence, no
>> need to create a new
>> >>>> concept!)
>> >>>>
>> >>>> See section 5.5.1 in the current Editor's draft
>> >>>>
>> http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-dm.html#term-specialization
>>
>> >>>>
>> >>>> Feedback welcome.
>> >>>>
>> >>>> Regards,
>> >>>> Luc
>> >>>>
>> >>>> PS. Tracker, this is ISSUE-385
>> >>>>
>> >>>
>> >>
>> >>
>>
>>
>>
>>
>> --
>> Jim McCusker
>> Programmer Analyst
>> Krauthammer Lab, Pathology Informatics
>> Yale School of Medicine
>> james.mccusker@yale.edu <mailto:james.mccusker@yale.edu> | (203) 785-6330
>> http://krauthammerlab.med.yale.edu
>>
>> PhD Student
>> Tetherless World Constellation
>> Rensselaer Polytechnic Institute
>> mccusj@cs.rpi.edu <mailto:mccusj@cs.rpi.edu>
>> http://tw.rpi.edu
>
Received on Thursday, 28 June 2012 08:46:15 UTC

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